Home

Description

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.

PUBLISHED Reserved 2026-06-21 | Published 2026-06-21 | Updated 2026-06-24 | Assigner VulnCheck




MEDIUM: 5.3CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
MEDIUM: 4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Problem types

Missing Authorization

Product status

Default status
unaffected

4.0.0-RC1 (semver) before 4.17.8
affected

4.17.8 (semver)
unaffected

5.0.0-RC1 (semver) before 5.9.14
affected

5.9.14 (semver)
unaffected

Credits

Susen2 reporter

References

github.com/...ms/cms/security/advisories/GHSA-x76w-8c62-48mg (GHSA Advisory GHSA-x76w-8c62-48mg) vendor-advisory

github.com/...ommit/d30df3112220db1ffd6726a3ed11857014c7fb27 patch

www.vulncheck.com/...zation-in-assets-preview-thumb-endpoint (VulnCheck Advisory: Craft CMS - Missing Authorization in assets/preview-thumb Endpoint) third-party-advisory

cve.org (CVE-2026-56384)

nvd.nist.gov (CVE-2026-56384)

Download JSON