{"id":"CVE-2026-45076","aliases":["GHSA-6qf2-7x63-mm6v","PYSEC-2026-194"],"url":"https://o3.security/vulnerability/CVE-2026-45076","summary":"Synapse pagination denial of service","details":"### Impact\n\nIn federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients.\n\nClients could therefore fail to display room history.\n\n### Patches\n\nUpdate to Synapse 1.152.1 or later.\n\n### Workarounds\n\nThere are no known workarounds for this issue.\n\n### Identifiers\n\n- ELEMENTSEC-2025-1636\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":"2026-05-28T15:50:25.842Z","modified":"2026-08-12T03:51:19.045554743Z","cvss":null,"epss":{"score":0.00369,"percentile":0.3001,"asOf":"2026-08-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"matrix-synapse","fixedVersion":"1.152.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45076.json"},{"type":"ADVISORY","url":"https://github.com/element-hq/synapse/security/advisories/GHSA-6qf2-7x63-mm6v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45076"},{"type":"PACKAGE","url":"https://github.com/element-hq/synapse"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2026-194.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:19.045554743Z"}}