GHSA-x76w-8c62-48mg: Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission
A vulnerability in Craft CMS allows authenticated control panel users without asset-view permission to access a signed fallback transform preview link for private assets via the assets/preview-thumb endpoint. This occurs because the endpoint does not perform an explicit permission check before generating the preview HTML. The issue can lead to unauthorized disclosure of private asset preview links, potentially increasing exposure risk depending on deployment context.
AI Analysis
Technical Summary
The vulnerability in Craft CMS involves the assets/preview-thumb endpoint accepting an attacker-controlled assetId parameter and returning thumbnail HTML containing a signed fallback transform link for that asset. The root cause is the lack of an explicit asset-view permission check before preview generation. Consequently, control panel users without permission to view certain private assets can still obtain signed preview transform link data, leading to unauthorized preview-link disclosure and missing authorization controls.
Potential Impact
Control panel users without permission to view private assets can obtain signed preview transform links, which may increase the risk of private asset exposure. The impact depends on the deployment and whether additional endpoint chaining or access methods can leverage this information. There is no indication of remote unauthenticated exploitation or privilege escalation beyond the existing control panel user privileges.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict control panel user permissions carefully to minimize exposure. Monitor vendor communications for updates addressing this authorization bypass issue.
GHSA-x76w-8c62-48mg: Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission
Description
A vulnerability in Craft CMS allows authenticated control panel users without asset-view permission to access a signed fallback transform preview link for private assets via the assets/preview-thumb endpoint. This occurs because the endpoint does not perform an explicit permission check before generating the preview HTML. The issue can lead to unauthorized disclosure of private asset preview links, potentially increasing exposure risk depending on deployment context.
CVSS v4.0
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Craft CMS involves the assets/preview-thumb endpoint accepting an attacker-controlled assetId parameter and returning thumbnail HTML containing a signed fallback transform link for that asset. The root cause is the lack of an explicit asset-view permission check before preview generation. Consequently, control panel users without permission to view certain private assets can still obtain signed preview transform link data, leading to unauthorized preview-link disclosure and missing authorization controls.
Potential Impact
Control panel users without permission to view private assets can obtain signed preview transform links, which may increase the risk of private asset exposure. The impact depends on the deployment and whether additional endpoint chaining or access methods can leverage this information. There is no indication of remote unauthenticated exploitation or privilege escalation beyond the existing control panel user privileges.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict control panel user permissions carefully to minimize exposure. Monitor vendor communications for updates addressing this authorization bypass issue.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-x76w-8c62-48mg
- Osv Schema Version
- 1.4.0
- Aliases
- []
- Ecosystems
- ["Packagist"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 4.0
Threat ID: 6a4c340627e9c797195f674f
Added to database: 07/06/2026, 23:02:30 UTC
Last enriched: 07/06/2026, 23:14:47 UTC
Last updated: 07/06/2026, 23:14:47 UTC
Views: 2
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