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Fencer Vulns
critical 9.8

CVE-2026-61560 json

@zereight/mcp-gitlab's unauthenticated arbitrary file read via `upload_markdown` enables PAT exfiltration and full account takeover

published 2026-09-15 54 d ago modified 2026-09-30 39 d ago also GHSA-cv3r-c5h8-f4g5 , EUVD-2026-80008

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known, plus a Nuclei check

Summary

`@zereight/mcp-gitlab` is a Model Context Protocol server for GitLab. Prior to version 2.1.27, the SSE transport mode (`SSE=true`) exposes all MCP tools without any authentication. The `upload_markdown` tool reads arbitrary files from the server's local filesystem via an unsanitized `file_path` parameter and uploads them to a GitLab project. Combined, any unauthenticated network-reachable attacker can read `/proc/self/environ` to steal the server's `GITLAB_PERSONAL_ACCESS_TOKEN` and achieve full GitLab account takeover. This is the default configuration for Docker deployments. Version 2.1.27 contains a patch.

Patch / fix

  • npm @zereight/mcp-gitlab 2.1.27

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
53 d ago

Exploit prediction

2.90% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template GitLab MCP Server < 2.1.27 - Unauthenticated SSE Transport Access nuclei detection template
  • github.com https://github.com/zereight/gitlab-mcp/security/advisories/GHSA-cv3r-c5h8-f4g5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm @zereight/mcp-gitlab
<2.1.27
2.1.27

Affected products

  • zereight gitlab-mcp

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

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.