CVE-2026-42885 Audiobookshelf: Path prefix bypass in filesystem existence check leaks out-of-scope file existence
Authenticated users can bypass path validation to probe file existence outside authorized library folders in Audiobookshelf.
- 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-2026-42885?
CVE-2026-42885 is a medium-severity path traversal vulnerability in advplyr audiobookshelf, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Audiobookshelf is a self-hosted audiobook and podcast server. Prior to 2.32.2, the POST /api/filesystem/pathexists endpoint uses String.startsWith() to validate that a resolved file path is within a library folder. This check fails for sibling directories whose names share a common prefix (e.g., /audiobooks vs /audiobooks-private), allowing authenticated users with upload permission to probe file existence outside their authorized library folder boundaries. This vulnerability is fixed in 2.32.2.
Weakness: CWE-22
Which versions are affected by CVE-2026-42885?
How do I fix CVE-2026-42885?
No fix has been published for CVE-2026-42885 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-42885 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42885 exists.
Sources
Also known as GHSA-rhjg-p6cm-38w2.