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Fencer Vulns
medium 6.5

CVE-2025-66689 json

A path traversal vulnerability exists in Zen MCP Server before 9.8.2 that allows authenticated attackers to read arbitrary files on the sys…

published 2026-01-12 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-1917

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

A path traversal vulnerability exists in Zen MCP Server before 9.8.2 that allows authenticated attackers to read arbitrary files on the system. The vulnerability is caused by flawed logic in the is_dangerous_path() validation function that uses exact string matching against a blacklist of system directories. Attackers can bypass these restrictions by accessing subdirectories of blacklisted paths.

Patch / fix

  • busymac pal_mcp_server 9.8.2

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/BeehiveInnovations/zen-mcp-server/issues/293 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/Team-Off-course/MCP-Server-Vuln-Analysis/blob/main/CVE-2025-66689.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-552 Files or Directories Accessible to External Parties

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.