{"id":"CVE-2026-48529","state":"PUBLISHED","title":"GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion","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.","publishedAt":"2026-06-26T16:33:32.688Z","updatedAt":"2026-06-27T02:43:34.588Z","severity":{"score":6,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["github github-mcp-server"],"affected":[{"vendor":"github","product":"github-mcp-server","versions":[{"version":">= 0.22.0, < 1.1.2","status":"affected"}]}],"references":["https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349"],"weaknesses":["CWE-284"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48529.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48529","state":"PUBLISHED","datePublished":"2026-06-26T16:33:32.688Z","dateUpdated":"2026-06-27T02:43:34.588Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-21T16:18:10.619Z"},"containers":{"cna":{"title":"GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"github","product":"github-mcp-server","versions":[{"version":">= 0.22.0, < 1.1.2","status":"affected"}]}],"references":[{"url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349","name":"https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-284","lang":"en","description":"CWE-284: Improper Access Control","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-26T16:33:32.688Z"},"source":{"advisory":"GHSA-pjp5-fpmr-3349","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-27T02:42:44.775898Z","id":"CVE-2026-48529","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-27T02:43:34.588Z"}}]}}}