{"cve":"CVE-2024-31208","nvd":{"published":"2024-04-23T18:15:14.457","modified":"2026-06-17T07:27:59.037","status":"Analyzed","description":"Synapse is an open-source Matrix homeserver. A 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 the V2 state resolution algorithm. This can induce high CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service. Servers in private federations, or those that do not federate, are not affected. Server administrators should upgrade to 1.105.1 or later. Some workarounds are available. One can ban the malicious users or ACL block servers from the rooms and/or leave the room and purge the room using the admin API.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-770"],"references":["https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a","https://github.com/element-hq/synapse/releases/tag/v1.105.1","https://github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R6FCCO4ODTZ3FDS7TMW76PKOSEL2TQVB/","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RR53FNHV446CB37TP45GZ6F6HZLZCK3K/"],"products":["fedoraproject:fedora","matrix:synapse"],"source":"nvd","synced_at":"2026-10-19T21:49:08.435428910+00:00"},"epss":{"cve":"CVE-2024-31208","score":0.01463,"percentile":0.73629,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-3h7q-rfh9-xm4v","url":"https://osv.dev/vulnerability/GHSA-3h7q-rfh9-xm4v","summary":"Synapse V2 state resolution weakness allows Denial of Service (DoS)","modified":"2026-09-10T03:50:11.151283540Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.105.1"],"fixed":["1.105.1"]}]},{"id":"PYSEC-2024-50","url":"https://osv.dev/vulnerability/PYSEC-2024-50","summary":"","modified":"2024-04-23T21:56:31.264267Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.105.1"],"fixed":["1.105.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}