CVE-2026-48529: CWE-284: Improper Access Control in github github-mcp-server
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.
AI Analysis
Technical Summary
GitHub MCP Server versions from 0.22.0 up to but not including 1.1.2 have an improper access control vulnerability (CWE-284) due to the RepoAccessCache being implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. When running in HTTP mode with --lockdown-mode enabled, all subsequent requests from different users share this singleton, causing their lockdown-related GraphQL queries to be executed with the first user's credentials. This flaw allows potential unauthorized access or privilege escalation within the server context. The vulnerability is resolved in version 1.1.2.
Potential Impact
The vulnerability allows subsequent users' requests to be executed with the credentials of the first authenticated user, potentially leading to unauthorized access or privilege escalation. The CVSS 3.1 score is 6.0 (medium severity), indicating a network attack vector requiring high attack complexity and low privileges, with no user interaction needed. The impact includes limited confidentiality, integrity, and availability loss.
Mitigation Recommendations
Upgrade GitHub MCP Server to version 1.1.2 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Patch status is confirmed fixed in 1.1.2.
CVE-2026-48529: CWE-284: Improper Access Control in github github-mcp-server
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 v3.1
Score 6.0medium
Affected software
pkg:github/github/github-mcp-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
GitHub MCP Server versions from 0.22.0 up to but not including 1.1.2 have an improper access control vulnerability (CWE-284) due to the RepoAccessCache being implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. When running in HTTP mode with --lockdown-mode enabled, all subsequent requests from different users share this singleton, causing their lockdown-related GraphQL queries to be executed with the first user's credentials. This flaw allows potential unauthorized access or privilege escalation within the server context. The vulnerability is resolved in version 1.1.2.
Potential Impact
The vulnerability allows subsequent users' requests to be executed with the credentials of the first authenticated user, potentially leading to unauthorized access or privilege escalation. The CVSS 3.1 score is 6.0 (medium severity), indicating a network attack vector requiring high attack complexity and low privileges, with no user interaction needed. The impact includes limited confidentiality, integrity, and availability loss.
Mitigation Recommendations
Upgrade GitHub MCP Server to version 1.1.2 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Patch status is confirmed fixed in 1.1.2.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-21T16:18:10.619Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3eae476e08203f7dc7e0c8
Added to database: 06/26/2026, 16:52:23 UTC
Last enriched: 07/03/2026, 22:35:52 UTC
Last updated: 08/09/2026, 02:52:38 UTC
Views: 88
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