Vulnerability · Published Jun 21, 2026 · Assigned by VulnCheck

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

Medium 4.3

In plain English

A medium-severity authorization bypass via user-controlled key in cms from craftcms. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.4%top 70.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	craftcms/cms	5.9.14	GHSA-44px-qjjc-xrhq
Packagist	craftcms/cms	4.17.8	GHSA-44px-qjjc-xrhq

Affected products (as reported)

Vendor	Product	Versions
craftcms	cms	5.0.0-RC1 – before 5.9.144.0.0-RC1 – before 4.17.8

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References

GHSA Advisory GHSA-44px-qjjc-xrhq vendor-advisory
https://github.com/craftcms/cms/commit/d30df3112220db1ffd6726a3ed11857014c7fb27 patch
VulnCheck Advisory: Craft CMS - Authorization Bypass in assets/preview-file Endpoint third-party-advisory