CVE-2026-48529 — MEDIUM (6.0)

Vulnerability Description

GitHub MCP Server is GitHub's official MCP Server. From 0.22.0 until 1.1.2, when running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. All subsequent requests from different users share this singleton and their lockdown-related GraphQL queries are executed using the first user's credentials. The singleton is never updated to reflect later users' tokens. This vulnerability is fixed in 1.1.2.

CVSS Score

6.0

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality

LOW

Integrity

LOW

Availability

LOW

Related Weaknesses (CWE)

CWE-284

References

FAQ

What is CVE-2026-48529?

CVE-2026-48529 is a vulnerability with a CVSS score of 6.0 (MEDIUM). GitHub MCP Server is GitHub's official MCP Server. From 0.22.0 until 1.1.2, when running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton ini...

How severe is CVE-2026-48529?

CVE-2026-48529 has been rated MEDIUM with a CVSS base score of 6.0/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-48529?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.