{"cve":"CVE-2026-45076","nvd":{"published":"2026-05-28T17:16:31.590","modified":"2026-10-26T13:10:00.140","status":"Analyzed","description":"Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","score":5.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L","score":2.7},"cwes":["CWE-20"],"references":["https://github.com/element-hq/synapse/security/advisories/GHSA-6qf2-7x63-mm6v"],"products":["element:synapse"],"source":"nvd","synced_at":"2026-10-26T13:39:24.642594360+00:00"},"epss":{"cve":"CVE-2026-45076","score":0.00369,"percentile":0.30513,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-6qf2-7x63-mm6v","url":"https://osv.dev/vulnerability/GHSA-6qf2-7x63-mm6v","summary":"Synapse pagination Denial of Service","modified":"2026-09-10T03:50:45.939755552Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.152.1"],"fixed":["1.152.1"]}]},{"id":"PYSEC-2026-194","url":"https://osv.dev/vulnerability/PYSEC-2026-194","summary":"","modified":"2026-06-05T12:45:16.338802941Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<1.152.1"],"fixed":["1.152.1"]}]}],"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."]}