Auth bypass in Craftcms Cms
CVE-2026-56384
Craft CMS contains a missing authorization vulnerability in the assets/preview-thumb endpoint. A Control Panel user without permission to view a target private asset can call the endpoint with an attacker-controlled assetId and receive preview HTML containing a signed fallback transform preview link for that private asset, because no asset-view permission check is performed before preview generation. This affects versions >= 4.0.0-RC1, <= 4.17.7 and >= 5.0.0-RC1, <= 5.9.13, and is fixed in 4.17.8 and 5.9.14.
Vulnerability class: Broken Access Control
EPSS: 0.003 (26.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
Affected products
- Craftcms Cms — versions 4.0.0-RC1, 4.17.8, 5.0.0-RC1
Weakness classification (CWE)
References
- disclosure@vulncheck.com (vendor-advisory)
- disclosure@vulncheck.com (patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-56384?
- CVE-2026-56384 is a medium-severity vulnerability in Craftcms Cms, classified under Missing Authorization. CVSS score: 4.3/10. Published 2026-06-21.
- How severe is CVE-2026-56384?
- Medium severity. CVSS v3 base score is 4.3 out of 10.