High severity8.7NVD Advisory· Published Sep 2, 2026
CVE-2026-84695
CVE-2026-84695
Description
BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.
Affected products
1- Range: <26.05.4
Patches
Vulnerability mechanics
References
5- github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.phpnvd
- github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420anvd
- github.com/BookStackApp/BookStack/releases/tag/v26.05.4nvd
- www.bookstackapp.com/blog/bookstack-release-v26-05-4/nvd
- www.vulncheck.com/advisories/bookstack-before-26.05.4-stored-xss-via-drawing-uploadnvd
News mentions
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