{"id":"UBUNTU-CVE-2024-31208","details":"Synapse is an open-source Matrix homeserver. A remote Matrix user with malicious intent, sharing a room with Synapse instances before 1.105.1, can dispatch specially crafted events to exploit a weakness in the V2 state resolution algorithm. This can induce high CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service. Servers in private federations, or those that do not federate, are not affected. Server administrators should upgrade to 1.105.1 or later. Some workarounds are available. One can ban the malicious users or ACL block servers from the rooms and/or leave the room and purge the room using the admin API.","modified":"2026-05-20T16:08:50.600471725Z","published":"2024-04-23T18:15:00Z","related":["USN-7444-1"],"upstream":["CVE-2024-31208"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2024-31208"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2024-31208"},{"type":"REPORT","url":"https://github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v"},{"type":"REPORT","url":"https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a"},{"type":"REPORT","url":"https://github.com/element-hq/synapse/releases/tag/v1.105.1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7444-1"}],"affected":[{"package":{"name":"synapse","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.1-1","0.2.99.2-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.2.99.2-1","binary_name":"synapse"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"matrix-synapse","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/matrix-synapse?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.2+dfsg-6","0.24.0+dfsg-1","0.24.0+dfsg-1ubuntu0.1~esm1","0.24.0+dfsg-1ubuntu0.1~esm4"],"ecosystem_specific":{"binaries":[{"binary_name":"matrix-synapse","binary_version":"0.24.0+dfsg-1ubuntu0.1~esm4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.2-3","0.2.99.3-1","0.2.99.4-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.2.99.4-1","binary_name":"synapse"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"matrix-synapse","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/matrix-synapse?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-1","1.4.0-1","1.5.0-1","1.5.1-1","1.6.0-1","1.6.1-1","1.7.0-2","1.7.1-1","1.7.2-1","1.7.3-1","1.8.0-1","1.9.0-1","1.9.1-1","1.10.0-1","1.10.0-2","1.11.0-1","1.11.0-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"matrix-synapse","binary_version":"1.11.0-1ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.4-2"],"ecosystem_specific":{"binaries":[{"binary_name":"synapse","binary_version":"0.2.99.4-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.4-3","0.2.99.4-3build1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.2.99.4-3build1","binary_name":"synapse"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"matrix-synapse","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/matrix-synapse?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.53.0-1ubuntu0.1~esm2"}]}],"versions":["1.39.0-1","1.47.0-2","1.47.1-1","1.48.0-1","1.49.0-1","1.49.2-1","1.50.1-1","1.50.2-1","1.51.0-1","1.52.0-1","1.53.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.53.0-1ubuntu0.1~esm2","binary_name":"matrix-synapse"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"matrix-synapse","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/matrix-synapse?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.90.0-1","1.100.0-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"matrix-synapse","binary_version":"1.100.0-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.4-4","0.2.99.4-4build1","0.2.99.4-4build2"],"ecosystem_specific":{"binaries":[{"binary_name":"synapse","binary_version":"0.2.99.4-4build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.4-4build2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.2.99.4-4build2","binary_name":"synapse"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.json"}},{"package":{"name":"synapse","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/synapse?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.2.99.4-4build2","0.2.99.4-4build3"],"ecosystem_specific":{"binaries":[{"binary_name":"synapse","binary_version":"0.2.99.4-4build3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2024/UBUNTU-CVE-2024-31208.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:N/A:H"},{"type":"Ubuntu","score":"medium"}]}