CVEvulnerability

CVE-2026-79534

5.9 MEDIUM Published 2026-09-29 Modified 2026-09-30 Official page ↗
Status
Deferred
Published
2026-09-29
Last modified
2026-09-30
Assigner
[email protected]
CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
5.9 MEDIUM — CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Weaknesses
CWE-22, CWE-59

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.

Related

Weakness · CWE (2)

  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory weakness
  • CWE-59 Improper Link Resolution Before File Access weakness

References