{"action":"Upgrade matrix-synapse to 1.41.1 or later.","affected":[{"fixed":"1.41.1","introduced":"0"}],"component":"matrix-synapse","cve_ids":["CVE-2021-39163"],"ecosystem":"PyPI","epss":0.00896,"exploited":false,"fixed_versions":["1.41.1"],"ghsa_id":"GHSA-jj53-8fmw-f2w2","id":"tcs_01M5KGCZFCN8GT7NDHATTMWEZH","modified_at":"2026-02-26T23:24:55.705814Z","published_at":"2021-08-31T16:15:00Z","references":["https://osv.dev/vulnerability/PYSEC-2021-424","https://github.com/matrix-org/synapse/security/advisories/GHSA-jj53-8fmw-f2w2","https://github.com/matrix-org/synapse/releases/tag/v1.41.1","https://github.com/matrix-org/synapse/commit/cb35df940a","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN/","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF/"],"severity":{"label":"unknown"},"sources":[{"source":"osv","source_id":"PYSEC-2021-424","url":"https://osv.dev/vulnerability/PYSEC-2021-424"}],"summary":"Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the name, avatar, topic and number of members of a room if th"}