{"id":"CVE-2018-16515","aliases":["DEBIAN-CVE-2018-16515","EUVD-2022-3811","GHSA-fmvh-rvq5-hhjx","PYSEC-2026-845","UBUNTU-CVE-2018-16515","USN-6076-1"],"status":"published","title":"Matrix Synapse Improper Signature Validation","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.","severity":{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.01538,"percentile":0.75062,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-347"],"published":"2018-09-18T21:00:00Z","modified":"2026-10-20T10:49:44Z","fixes":[{"ecosystem":"PyPI","package":"matrix-synapse","fixed_in":["0.33.3.1","0.33.2.1"],"sources":["ghsa","osv"]},{"ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","fixed_in":["0.24.0+dfsg-1ubuntu0.1~esm1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.33.3"},{"fixed":"0.33.3.1"}]}]},{"source":"ghsa","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.33.2.1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.33.3"},{"fixed":"0.33.3.1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.33.2.1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.33.2.1"},{"introduced":"0.33.3"},{"fixed":"0.33.3.1"}]}]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm1"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"matrix-synapse","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.24.0+dfsg-1ubuntu0.1~esm1"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1"],"bundled":7}],"products":[{"vendor":"debian","product":"debian_linux"},{"vendor":"matrix","product":"synapse"}],"references":[{"url":"https://github.com/matrix-org/synapse/issues/3796#event-1833126269","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred","web"]},{"url":"https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-16515","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/"},{"url":"https://github.com/matrix-org/synapse/commit/5bf8bc79ebc22c61968f2eb487714813fccbdb9b","tags":["web"]},{"url":"https://github.com/matrix-org/synapse/commit/804dd41e18c449e711e443398b95c9f6c68b6fa2","tags":["web"]},{"url":"https://github.com/matrix-org/synapse/commit/a5a0bf5cf71caed3c4e3677d2bce667c147dadfc","tags":["web"]},{"url":"https://github.com/matrix-org/synapse/commit/c127c8d0421f0228a46ebbe280c9537e8d8ea42b","tags":["web"]},{"url":"https://github.com/advisories/GHSA-fmvh-rvq5-hhjx","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2018-16515","tags":["advisory"]},{"url":"https://github.com/matrix-org/synapse","tags":["package"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P","tags":["web"]},{"url":"https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1","tags":["web","report"]},{"url":"https://pypi.org/project/matrix-synapse","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2018-16515","tags":["report"]},{"url":"https://matrix.org/blog/2018/09/05/pre-disclosure-upcoming-critical-security-fix-for-synapse/","tags":["report"]},{"url":"https://github.com/matrix-org/synapse/issues/3796","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-6076-1","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2018-16515","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-10657","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-12291","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2018-12423","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-5885","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-11842","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2019-18835","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2018-16515","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.","status":"published","published":"2018-09-18T21:00:00Z","modified":"2024-08-05T10:24:32.888Z","updated_at":"2026-11-02T14:35:11.426178Z"}],"euvd":[{"id":"EUVD-2022-3811","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.","status":"published","published":"2018-09-18T21:00:00Z","modified":"2024-08-05T10:24:32Z","updated_at":"2026-11-03T02:39:40.768074Z"}],"ghsa":[{"id":"GHSA-fmvh-rvq5-hhjx","title":"Matrix Synapse Improper Signature Validation","description":"Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.","status":"published","published":"2022-05-13T01:50:21Z","modified":"2023-10-06T17:19:34Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:37:08.278692Z"}],"nvd":[{"id":"CVE-2018-16515","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.","status":"published","published":"2018-09-18T21:29:03.01Z","modified":"2026-06-17T01:44:24.963Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"},{"version":"2.0","score":6.5,"vector":"AV:N/AC:L/Au:S/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:04:40.661264Z"}],"osv":[{"id":"CVE-2018-16515","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.","status":"published","published":"2018-09-18T21:29:03.01Z","modified":"2026-10-20T10:49:44.130108271Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:08.533609Z"},{"id":"DEBIAN-CVE-2018-16515","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.","status":"withdrawn","published":"2018-09-18T21:29:03.01Z","modified":"2026-08-11T20:49:50.099644185Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:30.290351Z"},{"id":"GHSA-fmvh-rvq5-hhjx","title":"Matrix Synapse Improper Signature Validation","description":"Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.","status":"published","published":"2022-05-13T01:50:21Z","modified":"2026-07-07T11:56:24.012556113Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:46:46.760785Z"},{"id":"PYSEC-2026-845","title":"Matrix Synapse Improper Signature Validation","description":"Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.","status":"published","published":"2026-07-06T08:03:21.195845Z","modified":"2026-07-07T11:46:05.85903058Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:52:58.117212Z"},{"id":"UBUNTU-CVE-2018-16515","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.","status":"published","published":"2018-09-18T21:29:00Z","modified":"2026-02-04T04:33:35.511136Z","cvss":[{"version":"3.0","score":8.8,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:54:17.496046Z"},{"id":"USN-6076-1","title":"matrix-synapse vulnerabilities","description":"It was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to cause a\ndenial of service. (CVE-2019-18835, CVE-2018-12291, CVE-2018-10657)\n\nIt was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to hijack the\nsession. (CVE-2019-11842, CVE-2018-12423)\n\nIt was discovered that Synapse incorrectly handled certain inputs. If a\nuser or an automated system were tricked into opening a specially crafted\ninput file, a remote attacker could possibly use this issue to perform \nspoofing or user impersonation. (CVE-2019-5885, CVE-2018-16515)\n","status":"published","published":"2023-05-16T07:45:08Z","modified":"2026-02-10T04:43:07Z","updated_at":"2026-11-02T16:58:16.738762Z"}]}}