CVE-2026-84695BookStack before 26.05.4 Stored XSS via Drawing Upload
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 8.7 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Deferred
- Record last updated
- Sep 2, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
bookstackapp bookstack bookstackapp:bookstack (from the name) | before 26.05.4; 26.05.4 not affected | CNA record |
References
- https://github.com/BookStackApp/BookStackproduct
- https://github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420apatch
- https://github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.phptechnical-description
- https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4release-notes
- https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/vendor-advisory
- https://www.vulncheck.com/advisories/bookstack-before-26.05.4-stored-xss-via-drawing-uploadthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.