CVE-2026-82450 BookStack before 26.05.4 Remote Code Execution via Book Cover
Attackers with import permissions can upload malicious PHP files as book covers to achieve remote code execution on BookStack instances.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-82450?
CVE-2026-82450 is a high-severity vulnerability in bookstackapp bookstack, published on 29 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests.
Weakness: CWE-434
Which versions are affected by CVE-2026-82450?
How do I fix CVE-2026-82450?
No fix has been published for CVE-2026-82450 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-82450 being exploited?
There is no known exploitation of CVE-2026-82450 in the wild and no public exploit code.
Sources
Also known as GHSA-jgmr-x24h-q8jj.