{"id":"UBUNTU-CVE-2019-18835","details":"Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. Events sent over /send_join, /send_leave, and /invite may not be correctly signed, or may not come from the expected servers.","modified":"2026-01-30T02:15:33.210753Z","published":"2019-11-08T00:15:00Z","related":["USN-6076-1"],"upstream":["CVE-2019-18835"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2019-18835"},{"type":"REPORT","url":"https://github.com/matrix-org/synapse/pull/6262"},{"type":"REPORT","url":"https://github.com/matrix-org/synapse/releases/tag/v1.5.0"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-6076-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2019-18835"}],"affected":[{"package":{"name":"matrix-synapse","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/matrix-synapse@0.24.0+dfsg-1ubuntu0.1~esm1?arch=source&distro=esm-apps/bionic"},"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"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"matrix-synapse","binary_version":"0.24.0+dfsg-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-18835.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}