CVE-2026-56384

Craft CMS - Missing Authorization in assets/preview-thumb Endpoint

Published Jun 21, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-x76w-8c62-48mg Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission
History
Type Values Removed Values Added
First Time appeared Craftcms
Craftcms craftcms
Vendors & Products Craftcms
Craftcms craftcms
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Craft CMS - Missing Authorization in assets/preview-thumb Endpoint
First Time appeared Juzaweb
Juzaweb cms
Weaknesses CWE-862
CPEs cpe:2.3:a:juzaweb:cms:*:*:*:*:*:*:*:*
Vendors & Products Juzaweb
Juzaweb cms
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Nov 8, 2026, 2:06 PM
Reserved
Jun 21, 2026, 2:05 AM
Status
Deferred
Published
Jun 21, 2026, 2:16 PM
Modified
Oct 25, 2026, 11:10 PM