{"cve":"CVE-2018-16515","nvd":{"published":"2018-09-18T21:29:03.010","modified":"2026-06-17T01:44:24.963","status":"Modified","description":"Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-347"],"references":["https://github.com/matrix-org/synapse/issues/3796#event-1833126269","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/","https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/","https://github.com/matrix-org/synapse/issues/3796#event-1833126269","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/"],"products":["debian:debian_linux","matrix:synapse"],"source":"nvd","synced_at":"2026-10-19T20:53:14.491561039+00:00"},"epss":{"cve":"CVE-2018-16515","score":0.01538,"percentile":0.74886,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-fmvh-rvq5-hhjx","url":"https://osv.dev/vulnerability/GHSA-fmvh-rvq5-hhjx","summary":"Matrix Synapse Improper Signature Validation","modified":"2026-07-07T11:56:24.012556113Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":[">=0.33.3 <0.33.3.1"],"fixed":["0.33.3.1"]},{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<0.33.2.1"],"fixed":["0.33.2.1"]}]},{"id":"PYSEC-2026-845","url":"https://osv.dev/vulnerability/PYSEC-2026-845","summary":"Matrix Synapse Improper Signature Validation","modified":"2026-07-07T11:46:05.859030580Z","packages":[{"ecosystem":"PyPI","name":"matrix-synapse","purl":"pkg:pypi/matrix-synapse","ranges":["<0.33.2.1",">=0.33.3 <0.33.3.1"],"fixed":["0.33.2.1","0.33.3.1"]}]}],"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."]}