CRITICAL 9.3 NVD
CVE-2026-84695
BookStack 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.
References
- https://github.com/BookStackApp/BookStack
- https://github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.php
- https://github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420a
- https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4
- https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/
This critical severity vulnerability with a CVSS score of 9.3 was published on 2026-09-02 via NVD.
Risk Timeline
CVE Disclosed2026-09-02 · -1 days ago
Remediation Resources
vulnfeed aggregates 11552 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.