{"action":"Upgrade matrix-synapse to 1.41.1 or later.","affected":[{"fixed":"1.41.1","introduced":"0"}],"component":"matrix-synapse","cve_ids":["CVE-2021-39164"],"ecosystem":"PyPI","epss":0.01451,"exploited":false,"fixed_versions":["1.41.1"],"ghsa_id":"GHSA-3x4c-pq33-4w3q","id":"tcs_01M5KEWR2GFB8WEG6B67XR7CWR","modified_at":"2026-07-08T06:28:52.954705259Z","published_at":"2021-09-01T18:25:27Z","references":["https://osv.dev/vulnerability/GHSA-3x4c-pq33-4w3q","https://github.com/matrix-org/synapse/security/advisories/GHSA-3x4c-pq33-4w3q","https://nvd.nist.gov/vuln/detail/CVE-2021-39164","https://github.com/matrix-org/synapse/commit/cb35df940a","https://github.com/matrix-org/synapse","https://github.com/matrix-org/synapse/releases/tag/v1.41.1","https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-425.yaml","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN"],"severity":{"label":"low","score":3.1},"sources":[{"source":"osv","source_id":"GHSA-3x4c-pq33-4w3q","url":"https://osv.dev/vulnerability/GHSA-3x4c-pq33-4w3q"}],"summary":"Improper authorisation of members discloses room membership to non-members"}