Quick answers
- Is CVE-2026-79534 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-79534 being exploited in the wild.
- How severe is CVE-2026-79534?
- Informational severity, published 29 September 2026.
- Which products and versions are affected?
- Mark3labs Mcp-Filesystem-Server v0.11.1 and main commit ba3f07f.
- Is there a fix for CVE-2026-79534?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-79534 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-79534?
- Check whether you run Mark3labs Mcp-Filesystem-Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The validatePath function in helper.go improperly handles dangling symlinks: when filepath.EvalSymlinks fails with os.IsNotExist, the code validates only the parent directory and returns the unresolved path instead of re-checking the final destination. This allows write_file, modify_file, copy_file, move_file, and create_directory operations to follow the planted symlink and write outside the allow-list. The vulnerability requires the attacker to pre-plant the symlink within an allowed directory.
Affected products
- mark3labs mcp-filesystem-server v0.11.1 and main commit ba3f07f
Timeline
- 2026-08-21: disclosed: Reported to maintainer by Traceforce
- 2026-09-10: advisory: CVE ID assigned by MITRE
- 2026-09-29: other: NVD publication