CVE-2026-33158: Craft CMS Low-privilege Users Could Read Private Vulnerability

MODERATE
Advisory Identifier: GHSA-3pvf-vxrv-hh9c
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CWE-639
Published
Advisory Summary

CVE-2026-33158 is a MODERATE low-privilege users could read private vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Craft CMS libraries in the Packagist ecosystem. The issue involves low-privilege users could read private asset contents when editing an asset (idor). Remediation is available by upgrading affected packages to version 4.17.8, 5.9.14.

CVE-2026-33158 at a Glance

CVE Identifier CVE-2026-33158
GHSA Identifier GHSA-3pvf-vxrv-hh9c
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Craft CMS
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-33158

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: 4.17.8 
Upgrade craftcms/cms to 4.17.8
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-2026-33158, 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 4.17.8), 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 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

### Summary A low-privileged authenticated user can read private asset content by calling `assets/edit-image` with an arbitrary `assetId` that they are not authorized to view. The endpoint returns image bytes (or a preview redirect) without enforcing a per-asset view authorization check, leading to potential unauthorized disclosure of private files. ### Details Root cause: - A user-controlled object reference (`assetId`) is used to load and return sensitive content. - The action does not verify whether the current user is authorized to view that asset. - This creates an authenticated IDOR / authorization bypass. ### Impact - Craft installations where private/non-public assets exist and low-privileged users can authenticate. ## Resources https://github.com/craftcms/cms/commit/7290d91639e

CVE-2026-33158 Affected Craft CMS Versions

2 component(s)
Fixed Versions:
4.17.85.9.14
Product / Package Ecosystem Affected Versions Fixed Version
craftcms/cms
 Packagist
≥ 4.0.0-RC1
< 4.17.8
4.17.8
craftcms/cms
 Packagist
≥ 5.0.0-RC1
< 5.9.14
5.9.14

References

GitHub Advisory / Wiki ADVISORY
https://github.com/craftcms/cms/security/advisories/GHSA-3pvf-vxrv-hh9c
NVD — CVE-2026-33158 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33158
Security Fix Commit FIX COMMIT
https://github.com/craftcms/cms/commit/7290d91639e5e3a4f7e221dfbef95c9b77331860
Craft CMS Source Repository REPOSITORY
https://github.com/craftcms/cms
Craft CMS Release RELEASE
https://github.com/craftcms/cms/releases/tag/4.17.8
Craft CMS Release RELEASE
https://github.com/craftcms/cms/releases/tag/5.9.14

Frequently Asked Questions

What is CVE-2026-33158?
CVE-2026-33158 is a security vulnerability in Craft CMS involving Low-privilege users could read private asset contents when editing an asset (IDOR) under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Craft CMS versions are affected?
Affected versions include releases prior to 4.17.8, 5.9.14 across affected packages: craftcms/cms.
What version fixes CVE-2026-33158?
Upgrading to 4.17.8, 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 4.17.8, 5.9.14. Upgrade your dependency to 4.17.8, 5.9.14 or later.
What CWE is associated with CVE-2026-33158?
CVE-2026-33158 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-2026-33158?
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-3pvf-vxrv-hh9c",
  "modified" : "2026-03-25T20:59:46Z",
  "published" : "2026-03-24T16:53:24Z",
  "aliases" : [ "CVE-2026-33158" ],
  "summary" : "Craft CMS: Low-privilege users could read private asset contents when editing an asset (IDOR)",
  "details" : "### Summary\n\nA low-privileged authenticated user can read private asset content by calling `assets/edit-image` with an arbitrary `assetId` that they are not authorized to view.\n\nThe endpoint returns image bytes (or a preview redirect) without enforcing a per-asset view authorization check, leading to potential unauthorized disclosure of private files.\n\n### Details\n\nRoot cause:\n  - A user-controlled object reference (`assetId`) is used to load and return sensitive content.\n  - The action does not verify whether the current user is authorized to view that asset.\n  - This creates an authenticated IDOR / authorization bypass.\n\n### Impact\n\n- Craft installations where private/non-public assets exist and low-privileged users can authenticate.\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:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "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"
    }
  }, {
    "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"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/cms/security/advisories/GHSA-3pvf-vxrv-hh9c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33158"
  }, {
    "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" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-24T16:53:24Z",
    "nvd_published_at" : "2026-03-24T18:16:09Z"
  }
}