CVE-2026-48529

Published: Jun 26, 2026Modified: Jun 27, 2026Deferred

6.0

Vector

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

Exploitability: 1.8 / Impact: 3.7

Source: security-advisories@github.com (Secondary)

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.

Related CWEs

CWE-284

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

References (2)

https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349

Source: security-advisories@github.com

https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Timeline

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