CVE-2026-56382: Craft CMS Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-86vw-x4ww-x467
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CWE-94
Published
Advisory Summary

CVE-2026-56382 is a HIGH remote code execution vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Craft CMS libraries in the Packagist ecosystem. The issue involves rce via missing cleanseconfig in fieldscontroller::actionrendercardpreview. Remediation is available by upgrading affected packages to version 5.9.14.

CVE-2026-56382 at a Glance

CVE Identifier CVE-2026-56382
GHSA Identifier GHSA-86vw-x4ww-x467
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Craft CMS
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-56382

To remediate this vulnerability, upgrade all affected Craft 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: 5.9.14 
Upgrade craftcms/cms to 5.9.14
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-2026-56382, inspect your project dependencies for Craft CMS:

inspect dependencies for craftcms/cms

Analyze the terminal output to locate any version of Craft CMS in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.9.14), 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Craft 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

The `actionRenderCardPreview()` method in `FieldsController` passes the `fieldLayoutConfig` POST parameter directly to `Fields::createLayout()` without calling `Component::cleanseConfig()`. This allows Yii2 event handler injection via `on eventName` keys in the config array, leading to arbitrary code execution. This is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, `_fldComponent` method correctly uses `cleanseConfig`), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController). ## PoC As an admin user with a valid session: ``` POST /admin/actions/fields/render-card-preview HTTP/1.1 Content-Type: application/x-www-form-urlencoded Cookie: CraftSessionId=<session> fieldLayoutConfig[on+init]=phpinfo&CRAFT_CSRF_TOKEN=<token> ``` When the FieldLayout object is constructed, Yii2 processes the `on init` key as an event handler registration. During `Component::init()`, the `init` event is triggered, calling `phpinfo()`. The phpinfo output (which includes environment variables, potentially containing database credentials and `CRAFT_SECURITY_KEY`) will appear in the response. ## Impact An authenticated admin can achieve RCE through Yii2 event handler injection. While this requires admin access (same as GHSA-4484-8v2f-5748, which was rated moderate), it allows arbitrary PHP function execution and information disclosure via phpinfo.

CVE-2026-56382 Affected Craft CMS Versions

1 component(s)
Fixed Versions:
5.9.14
Product / Package Ecosystem Affected Versions Fixed Version
craftcms/cms
 Packagist
≥ 5.5.0
< 5.9.14
5.9.14

References

GitHub Advisory / Wiki ADVISORY
https://github.com/craftcms/cms/security/advisories/GHSA-86vw-x4ww-x467
NVD — CVE-2026-56382 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56382
Craft CMS Source Repository REPOSITORY
https://github.com/craftcms/cms
www.vulncheck.com/advisories/craft-cm... WEB
https://www.vulncheck.com/advisories/craft-cms-remote-code-execution-via-missing-config-sanitization-in-fieldscontroller

Frequently Asked Questions

What is CVE-2026-56382?
CVE-2026-56382 is a security vulnerability in Craft CMS involving RCE via missing cleanseConfig in FieldsController::actionRenderCardPreview under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Craft CMS versions are affected?
Affected versions include releases prior to 5.9.14 across affected packages: craftcms/cms.
What version fixes CVE-2026-56382?
Upgrading to 5.9.14 (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 5.9.14. Upgrade your dependency to 5.9.14 or later.
What CWE is associated with CVE-2026-56382?
CVE-2026-56382 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Packagist dependencies for CVE-2026-56382?
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-86vw-x4ww-x467",
  "modified" : "2026-08-06T21:41:24Z",
  "published" : "2026-07-09T13:44:12Z",
  "aliases" : [ "CVE-2026-56382" ],
  "summary" : "Craft CMS: RCE via missing cleanseConfig in FieldsController::actionRenderCardPreview",
  "details" : "The `actionRenderCardPreview()` method in `FieldsController` passes the `fieldLayoutConfig` POST parameter directly to `Fields::createLayout()` without calling `Component::cleanseConfig()`. This allows Yii2 event handler injection via `on eventName` keys in the config array, leading to arbitrary code execution.\n\nThis is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, `_fldComponent` method correctly uses `cleanseConfig`), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController).\n\n## PoC\n\nAs an admin user with a valid session:\n\n```\nPOST /admin/actions/fields/render-card-preview HTTP/1.1\nContent-Type: application/x-www-form-urlencoded\nCookie: CraftSessionId=<session>\n\nfieldLayoutConfig[on+init]=phpinfo&CRAFT_CSRF_TOKEN=<token>\n```\n\nWhen the FieldLayout object is constructed, Yii2 processes the `on init` key as an event handler registration. During `Component::init()`, the `init` event is triggered, calling `phpinfo()`. The phpinfo output (which includes environment variables, potentially containing database credentials and `CRAFT_SECURITY_KEY`) will appear in the response.\n\n## Impact\n\nAn authenticated admin can achieve RCE through Yii2 event handler injection. While this requires admin access (same as GHSA-4484-8v2f-5748, which was rated moderate), it allows arbitrary PHP function execution and information disclosure via phpinfo.",
  "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" : "5.5.0"
      }, {
        "fixed" : "5.9.14"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.9.13"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-86vw-x4ww-x467"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-56382"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/craft-cms-remote-code-execution-via-missing-config-sanitization-in-fieldscontroller"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-09T13:44:12Z",
    "nvd_published_at" : null
  }
}