CVE-2026-33160: Craftcms/cms Craft CMS May Expose Private Vulnerability

LOW
Advisory Identifier: GHSA-5pgf-h923-m958
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CWE-639 CWE-862
Published
Advisory Summary

CVE-2026-33160 is a LOW craft cms may expose private vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Craftcms/cms libraries in the Packagist ecosystem. The issue involves craft cms may expose private assets through anonymous "generate transform" calls via transform url. Remediation is available by upgrading affected packages to version 5.9.14, 4.17.8.

CVE-2026-33160 at a Glance

CVE Identifier CVE-2026-33160
GHSA Identifier GHSA-5pgf-h923-m958
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Craftcms/cms
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-33160

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: 5.9.14 
Upgrade craftcms/cms to 5.9.14
craftcms/cms fixed: 4.17.8 
Upgrade craftcms/cms to 4.17.8
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-2026-33160, 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 5.9.14), 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. 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

### Summary An unauthenticated user can call `assets/generate-transform` with a private `assetId`, receive a valid transform URL, and fetch transformed image bytes. The endpoint is anonymous and does not enforce per-asset authorization before returning the transform URL. ### Details Root cause: - Anonymous endpoint accepts user-controlled asset reference. - It creates and returns a transform URL for that asset without checking access rights. - If the transform output is reachable, guest users can read content derived from private assets. Who is impacted: - Installations where private source assets can be transformed and transform URLs are reachable. Security consequence: - Anonymous users can obtain content derived from private assets without authentication. ### Resources https://github.com/craftcms/cms/commit/7290d91639e

CVE-2026-33160 Affected Craftcms/cms Versions

2 component(s)
Fixed Versions:
5.9.144.17.8
Product / Package Ecosystem Affected Versions Fixed Version
craftcms/cms
 Packagist
≥ 5.0.0-RC1
< 5.9.14
5.9.14
craftcms/cms
 Packagist
≥ 4.0.0-RC1
< 4.17.8
4.17.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/craftcms/cms/security/advisories/GHSA-5pgf-h923-m958
NVD — CVE-2026-33160 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33160
Security Fix Commit FIX COMMIT
https://github.com/craftcms/cms/commit/7290d91639e5e3a4f7e221dfbef95c9b77331860
Craftcms/cms Source Repository REPOSITORY
https://github.com/craftcms/cms
Craftcms/cms Release RELEASE
https://github.com/craftcms/cms/releases/tag/4.17.8
Craftcms/cms Release RELEASE
https://github.com/craftcms/cms/releases/tag/5.9.14

Frequently Asked Questions

What is CVE-2026-33160?
CVE-2026-33160 is a security vulnerability in Craftcms/cms involving Craft CMS may expose private assets through anonymous "generate transform" calls via transform URL under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Craftcms/cms versions are affected?
Affected versions include releases prior to 5.9.14, 4.17.8 across affected packages: craftcms/cms.
What version fixes CVE-2026-33160?
Upgrading to 5.9.14, 4.17.8 (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, 4.17.8. Upgrade your dependency to 5.9.14, 4.17.8 or later.
What CWE is associated with CVE-2026-33160?
CVE-2026-33160 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check Packagist dependencies for CVE-2026-33160?
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-5pgf-h923-m958",
  "modified" : "2026-03-25T21:00:12Z",
  "published" : "2026-03-24T16:59:58Z",
  "aliases" : [ "CVE-2026-33160" ],
  "summary" : "Craft CMS may expose private assets through anonymous \"generate transform\" calls via transform URL",
  "details" : "### Summary\n\nAn unauthenticated user can call `assets/generate-transform` with a private `assetId`, receive a valid transform URL, and fetch transformed image bytes.\n\nThe endpoint is anonymous and does not enforce per-asset authorization before returning the transform URL.\n\n### Details\n\nRoot cause:\n- Anonymous endpoint accepts user-controlled asset reference.\n- It creates and returns a transform URL for that asset without checking access rights.\n- If the transform output is reachable, guest users can read content derived from private assets.\n\nWho is impacted:\n\n- Installations where private source assets can be transformed and transform URLs are reachable.\n\nSecurity consequence:\n\n  - Anonymous users can obtain content derived from private assets without authentication.\n\n### Resources\n\nhttps://github.com/craftcms/cms/commit/7290d91639e",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0-RC1"
      }, {
        "fixed" : "5.9.14"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.9.13"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0-RC1"
      }, {
        "fixed" : "4.17.8"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.17.7"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-5pgf-h923-m958"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33160"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/commit/7290d91639e5e3a4f7e221dfbef95c9b77331860"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/cms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/releases/tag/4.17.8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/releases/tag/5.9.14"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639", "CWE-862" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-24T16:59:58Z",
    "nvd_published_at" : "2026-03-24T18:16:10Z"
  }
}