{"id":"UBUNTU-CVE-2021-45105","details":"Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.","modified":"2026-06-01T07:15:11.846047815Z","published":"2021-12-19T00:00:00Z","related":["USN-5203-1","USN-5222-1"],"upstream":["CVE-2021-45105"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-45105"},{"type":"REPORT","url":"https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/Log4Shell"},{"type":"REPORT","url":"https://logging.apache.org/log4j/2.x/security.html#CVE-2021-45105"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5203-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5222-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-45105"}],"affected":[{"package":{"name":"apache-log4j2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j2?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2-1","2.4-1","2.4-2","2.4-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.4-2ubuntu0.1~esm1","binary_name":"liblog4j2-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-45105.json"}},{"package":{"name":"apache-log4j2","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j2?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.12.4-0ubuntu0.1"}]}],"versions":["2.8.2-1","2.8.2-2","2.10.0-1","2.10.0-2","2.10.0-2ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.12.4-0ubuntu0.1","binary_name":"liblog4j2-java"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-45105.json"}},{"package":{"name":"apache-log4j2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.17.0-0.20.04.1"}]}],"versions":["2.11.1-2","2.11.2-1","2.15.0-0.20.04.1","2.16.0-0.20.04.1"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j2-java","binary_version":"2.17.0-0.20.04.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-45105.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}