{"id":"UBUNTU-CVE-2026-34479","details":"The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. Two groups of users are affected:   *  Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.   *  Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue. Note: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the  Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.","modified":"2026-05-20T16:12:55.176688971Z","published":"2026-04-10T16:16:00Z","upstream":["CVE-2026-34479"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-34479"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-34479"},{"type":"REPORT","url":"https://lists.apache.org/thread/gd0hp6mj17rn3kj279vgy4p7kd4zz5on"},{"type":"REPORT","url":"https://logging.apache.org/security.html#CVE-2026-34479"},{"type":"REPORT","url":"https://github.com/apache/logging-log4j2/pull/4078"},{"type":"REPORT","url":"https://logging.apache.org/cyclonedx/vdr.xml"},{"type":"REPORT","url":"https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html"},{"type":"REPORT","url":"http://www.openwall.com/lists/oss-security/2026/04/10/8"}],"affected":[{"package":{"name":"apache-log4j1.2","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j1.2?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.17-3ubuntu1","1.2.17-4ubuntu1","1.2.17-4ubuntu2","1.2.17-4ubuntu3","1.2.17-4ubuntu3+esm1","1.2.17-4ubuntu3+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j1.2-java","binary_version":"1.2.17-4ubuntu3+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.json"}},{"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/2026/UBUNTU-CVE-2026-34479.json"}},{"package":{"name":"apache-log4j1.2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j1.2?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.17-6ubuntu1","1.2.17-7ubuntu1","1.2.17-7ubuntu1+esm1","1.2.17-7ubuntu1+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j1.2-java","binary_version":"1.2.17-7ubuntu1+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.json"}},{"package":{"name":"apache-log4j1.2","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j1.2?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.17-7ubuntu2","1.2.17-8","1.2.17-8+deb10u1build0.18.04.1","1.2.17-8+deb10u1ubuntu0.1","1.2.17-8+deb10u1ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j1.2-java","binary_version":"1.2.17-8+deb10u1ubuntu0.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.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"}]}],"versions":["2.8.2-1","2.8.2-2","2.10.0-1","2.10.0-2","2.10.0-2ubuntu0.1","2.12.4-0ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j2-java","binary_version":"2.12.4-0ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.json"}},{"package":{"name":"apache-log4j1.2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j1.2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.17-8","1.2.17-9","1.2.17-9ubuntu0.1","1.2.17-9ubuntu0.2"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j1.2-java","binary_version":"1.2.17-9ubuntu0.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.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"}]}],"versions":["2.11.1-2","2.11.2-1","2.15.0-0.20.04.1","2.16.0-0.20.04.1","2.17.0-0.20.04.1","2.17.1-0.20.04.1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.17.1-0.20.04.1","binary_name":"liblog4j2-java"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34479.json"}},{"package":{"name":"apache-log4j1.2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/apache-log4j1.2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.17-10","1.2.17-11"],"ecosystem_specific":{"binaries":[{"binary_name":"liblog4j1.2-java","binary_version":"1.2.17-11"}]},"database_specific":{"source":"https://github.com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