{"id":"UBUNTU-CVE-2021-34431","details":"In Eclipse Mosquitto version 1.6 to 2.0.10, if an authenticated client that had connected with MQTT v5 sent a crafted CONNECT message to the broker a memory leak would occur, which could be used to provide a DoS attack against the broker.","modified":"2026-04-22T14:47:45.287242Z","published":"2021-07-22T14:15:00Z","related":["USN-6492-1"],"upstream":["CVE-2021-34431"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-34431"},{"type":"REPORT","url":"https://bugs.eclipse.org/bugs/show_bug.cgi?id=573191"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-6492-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-34431"}],"affected":[{"package":{"name":"mosquitto","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/mosquitto@1.6.9-1ubuntu0.1~esm1?arch=source&distro=esm-apps/focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.9-1ubuntu0.1~esm1"}]}],"versions":["1.6.6-1","1.6.7-1","1.6.8-1","1.6.8-2","1.6.9-1~build1","1.6.9-1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"libmosquitto1","binary_version":"1.6.9-1ubuntu0.1~esm1"},{"binary_name":"libmosquittopp1","binary_version":"1.6.9-1ubuntu0.1~esm1"},{"binary_name":"mosquitto","binary_version":"1.6.9-1ubuntu0.1~esm1"},{"binary_name":"mosquitto-clients","binary_version":"1.6.9-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-34431.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"}]}