{"id":"CVE-2026-48529","summary":"GitHub MCP Server: Lockdown mode singleton in HTTP server causes cross-user GraphQL client confusion","details":"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.","aliases":["GHSA-pjp5-fpmr-3349","GO-2026-5779"],"modified":"2026-07-31T18:30:07.398054762Z","published":"2026-06-26T16:33:32.688Z","related":["openSUSE-SU-2026:21483-1"],"database_specific":{"cwe_ids":["CWE-284"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48529.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48529.json"},{"type":"ADVISORY","url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48529"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/github/github-mcp-server","events":[{"introduced":"6a57e75d729f9767827bc4f96e80ff9bd8538a46"},{"fixed":"b5397f6e3305531a1c534b90b2d347a70fa84da9"}],"database_specific":{"extracted_events":[{"introduced":"0.22.0"},{"fixed":"1.1.2"}],"source":"AFFECTED_FIELD"}}],"versions":["v1.1.1","v1.1.0","v1.0.5","v1.0.4","v1.0.3","v1.0.2","v1.0.1","v1.0.0","v0.33.1","v0.33.0","v0.32.0","v0.31.0","v0.30.3","v0.30.2","v0.30.1","v0.30.0","v0.29.0","v0.28.1","v0.28.0","v0.27.0","v0.26.3","v0.26.2","v0.26.1","v0.26.0","v0.25.0","v0.24.1","v0.24.0","v0.22.0","v0.23.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48529.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L"}]}