{"id":"CVE-2018-10657","aliases":["GHSA-vmcc-4p4x-x7wg","PYSEC-2026-846"],"url":"https://o3.security/vulnerability/CVE-2018-10657","summary":"Matrix Synapse DoS","details":"Matrix Synapse before 0.28.1 is prone to a denial of service flaw where malicious events injected with depth = 2^63 - 1 render rooms unusable, related to federation/federation_base.py and handlers/message.py, as exploited in the wild in April 2018.","published":"2018-05-02T16:29:00.233Z","modified":"2026-07-08T14:59:18.771813Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"PyPI","name":"matrix-synapse","fixedVersion":"0.28.1"}],"fix":{"url":"https://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb","label":"matrix-org/synapse@33f469b"},"references":[{"type":"ADVISORY","url":"https://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1/"},{"type":"FIX","url":"https://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2018-10657"},{"type":"WEB","url":"https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI/edit#heading=h.fj95ykuss7s1"},{"type":"PACKAGE","url":"https://github.com/matrix-org/synapse"},{"type":"WEB","url":"https://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T14:59:18.771813Z"}}