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.
Published: 2026-06-26
Score: 6 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-pjp5-fpmr-3349 GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion
History

Mon, 29 Jun 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Github
Github github-mcp-server
Vendors & Products Github
Github github-mcp-server

Sat, 27 Jun 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 26 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
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.
Title GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion
Weaknesses CWE-284
References
Metrics cvssV3_1

{'score': 6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L'}


Subscriptions

Github Github-mcp-server
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-27T02:43:34.588Z

Reserved: 2026-05-21T16:18:10.619Z

Link: CVE-2026-48529

cve-icon Vulnrichment

Updated: 2026-06-27T02:43:21.930Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-29T20:06:16Z

Weaknesses