{"id":"CVE-2025-30355","summary":"Synapse vulnerable to federation denial of service via malformed events","details":"Synapse is an open source Matrix homeserver implementation. A malicious server can craft events which, when received, prevent Synapse version up to 1.127.0 from federating with other servers. The vulnerability has been exploited in the wild and has been fixed in Synapse v1.127.1. No known workarounds are available.","aliases":["GHSA-v56r-hwv5-mxg6"],"modified":"2026-04-10T05:24:46.263978Z","published":"2025-03-27T00:59:27.996Z","related":["openSUSE-SU-2025:14939-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-20"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30355.json"},"references":[{"type":"WEB","url":"https://github.com/element-hq/synapse/releases/tag/v1.127.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/30xxx/CVE-2025-30355.json"},{"type":"ADVISORY","url":"https://github.com/element-hq/synapse/security/advisories/GHSA-v56r-hwv5-mxg6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-30355"},{"type":"FIX","url":"https://github.com/element-hq/synapse/commit/2277df2a1eb685f85040ef98fa21d41aa4cdd389"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/element-hq/synapse","events":[{"introduced":"0"},{"fixed":"2277df2a1eb685f85040ef98fa21d41aa4cdd389"}]},{"type":"GIT","repo":"https://github.com/element-hq/synapse","events":[{"introduced":"0"},{"fixed":"ecc09b15f108a49348777c908af0187cf26d281e"}]}],"versions":["hhs-1","hhs-2","hhs-3","hhs-5","hhs-6","hhs-7","hhs-8","v0.10.0","v0.10.0-r1","v0.10.0-r2","v0.11.0","v0.11.0-r1","v0.11.0-r2","v0.11.1","v0.12.0","v0.13.1","v0.13.2","v0.13.3","v0.14.0","v0.16.0","v0.16.1","v0.16.1-r1","v0.17.0","v0.17.1","v0.17.2","v0.17.3","v0.18.0","v0.18.1","v0.18.2","v0.18.3","v0.18.4","v0.18.5","v0.2.0","v0.2.1","v0.2.1a","v0.2.2","v0.23.0-rc1","v0.23.0-rc2","v0.25.0-rc1","v0.28.0-rc1","v0.3.0","v0.3.3","v0.3.4","v0.32.0","v0.32.0rc1","v0.32.2","v0.4.1","v0.4.2","v0.5.0","v0.5.1","v0.5.2","v0.5.3","v0.5.3a","v0.5.3b","v0.5.3c","v0.5.4","v0.5.4a","v0.6.0","v0.6.0a","v0.6.0b","v0.6.1","v0.6.1a","v0.6.1b","v0.6.1c","v0.6.1d","v0.6.1e","v0.6.1f","v0.7.0","v0.7.0a","v0.7.0b","v0.7.0c","v0.7.0d","v0.7.0e","v0.7.0f","v0.7.1","v0.7.1-r1","v0.7.1-r2","v0.7.1-r3","v0.7.1-r4","v0.8.0","v0.8.1","v0.8.1-r1","v0.8.1-r2","v0.8.1-r3","v0.8.1-r4","v0.9.0","v0.9.0-r1","v0.9.0-r2","v0.9.0-r3","v0.9.0-r4","v0.9.0-r5","v0.9.1","v0.9.2","v0.9.2-r1","v0.9.2-r2","v0.9.3","v0.99.1rc1","v0.99.2rc1","v0.99.4rc1","v0.99.5.1.dev0","v1.1.0rc1","v1.1.0rc2","v1.10.0rc1","v1.100.0rc1","v1.100.0rc2","v1.100.0rc3","v1.101.0rc1","v1.103.0rc1","v1.104.0rc1","v1.105.0rc1","v1.106.0rc1","v1.11.0rc1","v1.111.0rc1","v1.112.0rc1","v1.114.0rc1","v1.115.0rc1","v1.116.0rc1","v1.12.0rc1","v1.121.0rc1","v1.123.0rc1","v1.124.0rc1","v1.126.0rc1","v1.126.0rc2","v1.126.0rc3","v1.127.0","v1.127.0rc1","v1.14.0rc1","v1.15.0rc1","v1.16.0rc1","v1.17.0rc1","v1.18.0rc1","v1.23.0rc1","v1.24.0rc1","v1.27.0rc1","v1.29.0rc1","v1.3.0rc1","v1.30.0rc1","v1.31.0rc1","v1.32.0rc1","v1.34.0rc1","v1.35.0rc1","v1.36.0rc1","v1.4.0rc1","v1.40.0rc1","v1.49.0rc1","v1.5.0rc1","v1.52.0rc1","v1.6.0rc1","v1.62.0rc1","v1.63.0rc1","v1.75.0rc1","v1.76.0rc1","v1.78.0rc1","v1.79.0rc1","v1.8.0rc1","v1.81.0rc1","v1.84.0rc1","v1.87.0rc1","v1.88.0rc1","v1.9.0.dev1","v1.9.0.dev2","v1.9.0rc1","v1.90.0rc1","v1.94.0rc1","v1.95.0rc1","v1.98.0rc1","v1.99.0rc1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-30355.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H"}]}