{"id":"CVE-2024-31208","aliases":["GHSA-3h7q-rfh9-xm4v","PYSEC-2024-50"],"url":"https://o3.security/vulnerability/CVE-2024-31208","summary":"Synapse's V2 state resolution weakness allows DoS from remote room members","details":"### Impact\n\nA remote Matrix user with malicious intent, sharing a room with Synapse instances before 1.105.1, can dispatch specially crafted events to exploit a weakness in how the auth chain cover index is calculated. This can induce high CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service.\n\nServers in private federations, or those that do not federate, are not affected.\n\n### Patches\n\nServer administrators should upgrade to 1.105.1 or later.\n\n### Workarounds\n\nOne can:\n- ban the malicious users or ACL block servers from the rooms; and/or\n- leave the room and purge the room using the admin API\n\n### For more information\n\nIf you have any questions or comments about this advisory, please email us at [security AT element.io](mailto:security@element.io).","published":"2024-04-23T17:26:39.171Z","modified":"2026-08-12T03:51:31.487274916Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"matrix-synapse","fixedVersion":"1.105.1"}],"fix":{"url":"https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a","label":"element-hq/synapse@55b0aa8"},"references":[{"type":"WEB","url":"https://github.com/element-hq/synapse/releases/tag/v1.105.1"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R6FCCO4ODTZ3FDS7TMW76PKOSEL2TQVB/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RR53FNHV446CB37TP45GZ6F6HZLZCK3K/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSF4NJJSTSQRJQ47PLYYSCFYKJBP7DET/"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/31xxx/CVE-2024-31208.json"},{"type":"ADVISORY","url":"https://github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-31208"},{"type":"FIX","url":"https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a"},{"type":"PACKAGE","url":"https://github.com/element-hq/synapse"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2024-50.yaml"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R6FCCO4ODTZ3FDS7TMW76PKOSEL2TQVB"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RR53FNHV446CB37TP45GZ6F6HZLZCK3K"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSF4NJJSTSQRJQ47PLYYSCFYKJBP7DET"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:31.487274916Z"}}