CVE-2026-56385: Authorization Bypass Through User-Controlled Key in craftcms cms
Craft CMS versions >= 5.0.0-RC1, <= 5.9.13 and >= 4.0.0-RC1, <= 4.17.7 contain an authorization bypass in the assets/preview-file endpoint. The action does not enforce per-asset view authorization before returning preview content, allowing an authenticated low-privileged user to supply a controlled assetId for an asset they are not permitted to view and still receive preview response data (previewHtml), including a private preview image route containing the target private assetId. Fixed in 5.9.14 and 4.17.8.
AI Analysis
Technical Summary
CVE-2026-56385 is an authorization bypass vulnerability affecting Craft CMS in versions >=4.0.0-RC1 and <=4.17.7, and >=5.0.0-RC1 and <=5.9.13. The issue exists in the assets/preview-file endpoint, where the system fails to enforce per-asset view authorization before returning preview content. As a result, an authenticated user with limited privileges can supply an arbitrary assetId and receive previewHtml content, including private preview image routes for assets they should not access. This vulnerability was addressed and fixed in Craft CMS versions 4.17.8 and 5.9.14.
Potential Impact
An authenticated low-privileged user can bypass authorization controls to view preview content of private assets they are not permitted to access. This exposure includes preview HTML and private preview image routes, potentially leaking sensitive asset information. The vulnerability does not require elevated privileges or user interaction beyond authentication.
Mitigation Recommendations
A fix is available in Craft CMS versions 4.17.8 and 5.9.14. Users should upgrade to these or later versions to remediate the vulnerability. No vendor advisory content was provided to indicate alternative mitigations or temporary fixes.
CVE-2026-56385: Authorization Bypass Through User-Controlled Key in craftcms cms
Description
Craft CMS versions >= 5.0.0-RC1, <= 5.9.13 and >= 4.0.0-RC1, <= 4.17.7 contain an authorization bypass in the assets/preview-file endpoint. The action does not enforce per-asset view authorization before returning preview content, allowing an authenticated low-privileged user to supply a controlled assetId for an asset they are not permitted to view and still receive preview response data (previewHtml), including a private preview image route containing the target private assetId. Fixed in 5.9.14 and 4.17.8.
CVSS v4.0
Score 5.3medium
Affected software
pkg:github/craftcms/cmsRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-56385 is an authorization bypass vulnerability affecting Craft CMS in versions >=4.0.0-RC1 and <=4.17.7, and >=5.0.0-RC1 and <=5.9.13. The issue exists in the assets/preview-file endpoint, where the system fails to enforce per-asset view authorization before returning preview content. As a result, an authenticated user with limited privileges can supply an arbitrary assetId and receive previewHtml content, including private preview image routes for assets they should not access. This vulnerability was addressed and fixed in Craft CMS versions 4.17.8 and 5.9.14.
Potential Impact
An authenticated low-privileged user can bypass authorization controls to view preview content of private assets they are not permitted to access. This exposure includes preview HTML and private preview image routes, potentially leaking sensitive asset information. The vulnerability does not require elevated privileges or user interaction beyond authentication.
Mitigation Recommendations
A fix is available in Craft CMS versions 4.17.8 and 5.9.14. Users should upgrade to these or later versions to remediate the vulnerability. No vendor advisory content was provided to indicate alternative mitigations or temporary fixes.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-06-21T02:05:47.495Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a37ed4baaf2dc2701b22769
Added to database: 06/21/2026, 13:55:23 UTC
Last enriched: 06/28/2026, 21:58:11 UTC
Last updated: 08/05/2026, 08:09:10 UTC
Views: 87
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