CVE-2026-84695 BookStack before 26.05.4 Stored XSS via Drawing Upload
Attackers with editor permissions can inject scripts via SVG uploads that execute in administrator browsers, potentially leading to account takeover.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-84695?
CVE-2026-84695 is a critical cross-site scripting vulnerability in bookstackapp bookstack, published on 2 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-84695?
How do I fix CVE-2026-84695?
No fix has been published for CVE-2026-84695 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-84695 being exploited?
There is no known exploitation of CVE-2026-84695 in the wild and no public exploit code.
Sources
Also known as GHSA-r46q-wv4x-rj72.