CVE-2026-48529 - GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion
CVE ID :CVE-2026-48529
Published : June 26, 2026, 4:33 p.m. | 2 hours, 8 minutes ago
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.
Severity: 0.0 | NA
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Published : June 26, 2026, 4:33 p.m. | 2 hours, 8 minutes ago
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.
Severity: 0.0 | NA
Visit the link for more details, such as CVSS details, affected products, timeline, and more...