{"id":"UBUNTU-CVE-2021-20237","details":"An uncontrolled resource consumption (memory leak) flaw was found in ZeroMQ's src/xpub.cpp in versions before 4.3.3. This flaw allows a remote unauthenticated attacker to send crafted PUB messages that consume excessive memory if the CURVE/ZAP authentication is disabled on the server, causing a denial of service. The highest threat from this vulnerability is to system availability.","modified":"2026-01-30T01:13:54.676957Z","published":"2021-05-28T11:15:00Z","related":["USN-4920-1"],"upstream":["CVE-2021-20237"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-20237"},{"type":"REPORT","url":"https://github.com/zeromq/libzmq/security/advisories/GHSA-4p5v-h92w-6wxw"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4920-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-20237"}],"affected":[{"package":{"name":"zeromq3","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/zeromq3@4.2.5-1ubuntu0.2+esm2?arch=source&distro=esm-apps/bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.5-1ubuntu0.2+esm2"}]}],"versions":["4.2.1-4ubuntu1","4.2.2-1ubuntu2","4.2.3-1","4.2.3-1build1","4.2.5-1","4.2.5-1ubuntu0.1","4.2.5-1ubuntu0.2","4.2.5-1ubuntu0.2+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzmq3-dev","binary_version":"4.2.5-1ubuntu0.2+esm2"},{"binary_name":"libzmq5","binary_version":"4.2.5-1ubuntu0.2+esm2"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-20237.json"}},{"package":{"name":"zeromq3","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/zeromq3@4.3.2-2ubuntu1.20.04.1~esm2?arch=source&distro=esm-apps/focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.3.2-2ubuntu1.20.04.1~esm2"}]}],"versions":["4.3.2-1","4.3.2-2","4.3.2-2ubuntu1","4.3.2-2ubuntu1.20.04.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzmq3-dev","binary_version":"4.3.2-2ubuntu1.20.04.1~esm2"},{"binary_name":"libzmq5","binary_version":"4.3.2-2ubuntu1.20.04.1~esm2"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-20237.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:N/I:N/A:H"},{"type":"Ubuntu","score":"low"}]}