Nixpkgs security tracker
NIXPKGS-2026-2014
GitHub issue
published 6 hours ago
GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion
Permalink
CVE-2026-48529
6.0 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): High (H)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Scope (S): Changed (C)
- Confidentiality (C): Low (L)
- Integrity (I): Low (L)
- Availability (A): Low (L)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): High (H)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): Low (L)
- Modified Scope (MS): Changed (C)
- Modified Integrity (MI): Low (L)
- Modified Availability (MA): Low (L)
by @LeSuisse Activity log
- Created suggestion
- @LeSuisse accepted
- @LeSuisse published on GitHub
GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion
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.
References
Affected products
github-mcp-server
- ==>= 0.22.0, < 1.1.2
Package maintainers
-
@i-am-logger Ido Samuelson <ido.samuelson@gmail.com>