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VulnerabilityPublished Updated

craftcms/cms · Duplicate Advisory: Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission

Affects craftcms/cmsSource GCVE Database

0

CVSS 4.3 Medium · fixed in 4.17.8 : update craftcms/cms when convenient.

Data as of 7 Aug 2026, 07:00 UTC

CVSS 3.1 base score
4.3Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 4.17.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

What to do

Affected software

ProductAffectedFixed in
Packagistcraftcms/cmsAffected
  • >=4.0.0-RC1 <=4.17.7
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Craft CMS to version 4.17.8 or later in the 4.x series, or 5.9.14 or later in the 5.x series, where this vulnerability has been fixed. No other mitigations are indicated.

Description

Craft CMS versions 4.0.0-RC1 through 4.17.7 and 5.0.0-RC1 through 5.9.13 contain a missing authorization vulnerability in the assets/preview-thumb endpoint. This flaw allows Control Panel users without asset-view permission to obtain a signed fallback transform preview link for private assets by calling the endpoint with an attacker-controlled assetId. The vulnerability is fixed in versions 4.17.8 and 5.9.14.

References

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