Vulnerability · Published Sep 29, 2026 · Assigned by mitre
CVE-2026-79534
Medium 5.9
In plain English
A medium-severity path traversal in the affected software. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).
Official description
mark3labs mcp-filesystem-server v0.11.1 is vulnerable to Directory Traversal due to an improper link resolution in validatePath (filesystemserver/handler/helper.go). When filepath.EvalSymlinks returns os.IsNotExist for a dangling symlink, the fallback validates only the parent directory and returns the unresolved path, so write_file (and modify_file, copy_file, move_file, create_directory) follows a pre-existing dangling symlink located inside an allowed directory and creates a file outside the configured allowed directories.
Affected products (as reported)
Weakness: CWE-22, CWE-59 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N