GitLab MCP Server < 2.1.27 - Unauthenticated SSE Transport Access
CVE-2026-61560
Verified
Description
The @zereight/mcp-gitlab GitLab MCP server exposes its SSE transport endpoints without any authentication when SSE mode is enabled. An unauthenticated attacker with network access can establish an MCP session and invoke every registered tool, including upload_markdown, which reads arbitrary files from the server filesystem via an unsanitized file_path parameter.
Severity
Critical
CVSS Score
9.8
Exploit Probability
3%
Affected Product
gitlab-mcp
Published Date
September 19, 2026
Template Author
ashish-cybersec
CVE-2026-61560.yaml
9.8Score
CVSS Metrics
CVSS Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVE ID:
cve-2026-61560
CWE ID:
cwe-22
Remediation Steps
Update to @zereight/mcp-gitlab 2.1.27 or later, set SSE_AUTH_TOKEN, and bind the service to a loopback address.