CVE-2026-84695
highBookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores…
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/BookStackApp/BookStack disclosure@vulncheck.com
- https://github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.php disclosure@vulncheck.com
- https://github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420a disclosure@vulncheck.com
- https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4 disclosure@vulncheck.com
- https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/ disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/bookstack-before-26.05.4-stored-xss-via-drawing-uploa... disclosure@vulncheck.com