What’s Vulnerable › Vulnerabilities

CVE-2026-56385: Craft CMS - Authorization Bypass in assets/preview-file Endpoint

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-21 · updated 2026-10-25
• Weakness: CWE-639

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.

Affected products

• craftcms cms: from 5.0.0-RC1 before 5.9.14; from 4.0.0-RC1 before 4.17.8 — fixed in 4.17.8, 5.9.14

How to fix

Upgrade to a fixed version: craftcms cms 4.17.8, 5.9.14. Check the vendor advisory for mitigations.

References

• https://github.com/craftcms/cms/commit/d30df3112220db1ffd6726a3ed11857014c7fb27
• https://github.com/craftcms/cms/security/advisories/GHSA-44px-qjjc-xrhq
• https://www.vulncheck.com/advisories/craft-cms-authorization-bypass-in-assets-preview-file-endpoint

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