Answer in brief
CVE-2026-56384 records a Medium severity (CVSS 5.3) vulnerability in Craft CMS - Missing Authorization in assets/preview-thumb Endpoint. The current sources do not mark it as known exploited. The current feed maps craftcms/cms (composer), craftcms/cms (composer), craftcms/cms (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps craftcms/cms (composer), craftcms/cms (composer), craftcms/cms (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| craftcms/cmscomposer | >=4.0.0-RC1,<=4.17.7 | 4.17.8 |
| craftcms/cmscomposer | >=5.0.0-RC1,<=5.9.13 | 5.9.14 |
| craftcms/cmsgeneric | >=4.0.0-RC1 <4.17.8 || >=5.0.0-RC1 <5.9.14 | 4.17.8, 5.9.14 |
Published upstream
Jun 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.