{"action":"Upgrade matrix-synapse to 1.33.2 or later.","affected":[{"fixed":"1.33.2","introduced":"0"}],"component":"matrix-synapse","cve_ids":["CVE-2021-29471"],"ecosystem":"PyPI","epss":0.01647,"exploited":false,"fixed_versions":["1.33.2"],"ghsa_id":"GHSA-x345-32rc-8h85","id":"tcs_01M5KG389H371PE4PFXWHF98HK","modified_at":"2026-07-08T06:27:40.962217171Z","published_at":"2021-05-13T20:22:51Z","references":["https://osv.dev/vulnerability/GHSA-x345-32rc-8h85","https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85","https://nvd.nist.gov/vuln/detail/CVE-2021-29471","https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c","https://github.com/matrix-org/synapse","https://github.com/matrix-org/synapse/releases/tag/v1.33.2","https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-135.yaml","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY"],"severity":{"label":"low","score":3.7},"sources":[{"source":"osv","source_id":"GHSA-x345-32rc-8h85","url":"https://osv.dev/vulnerability/GHSA-x345-32rc-8h85"}],"summary":"Denial of service attack via push rule patterns in matrix-synapse"}