{"id":"UBUNTU-CVE-2026-5946","details":"Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.","modified":"2026-08-27T04:40:54.212403185Z","published":"2026-05-20T00:00:00Z","related":["USN-8293-1","USN-8682-1"],"upstream":["CVE-2026-5946"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-5946"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-5946"},{"type":"REPORT","url":"https://kb.isc.org/docs/cve-2026-5946"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8293-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8682-1"}],"affected":[{"package":{"name":"bind9","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/bind9?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:9.11.3+dfsg-1ubuntu1.19+esm5"}]}],"versions":["1:9.10.3.dfsg.P4-12.6ubuntu1","1:9.11.2.P1-1ubuntu2","1:9.11.2.P1-1ubuntu3","1:9.11.2.P1-1ubuntu4","1:9.11.2.P1-1ubuntu5","1:9.11.3+dfsg-1ubuntu1","1:9.11.3+dfsg-1ubuntu1.1","1:9.11.3+dfsg-1ubuntu1.2","1:9.11.3+dfsg-1ubuntu1.3","1:9.11.3+dfsg-1ubuntu1.5","1:9.11.3+dfsg-1ubuntu1.7","1:9.11.3+dfsg-1ubuntu1.8","1:9.11.3+dfsg-1ubuntu1.9","1:9.11.3+dfsg-1ubuntu1.10","1:9.11.3+dfsg-1ubuntu1.11","1:9.11.3+dfsg-1ubuntu1.12","1:9.11.3+dfsg-1ubuntu1.13","1:9.11.3+dfsg-1ubuntu1.14","1:9.11.3+dfsg-1ubuntu1.15","1:9.11.3+dfsg-1ubuntu1.16","1:9.11.3+dfsg-1ubuntu1.17","1:9.11.3+dfsg-1ubuntu1.18","1:9.11.3+dfsg-1ubuntu1.19+esm1","1:9.11.3+dfsg-1ubuntu1.19+esm2","1:9.11.3+dfsg-1ubuntu1.19+esm3","1:9.11.3+dfsg-1ubuntu1.19+esm4"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro (Infra-only): 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with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5946.json"}},{"package":{"name":"bind9-libs","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/bind9-libs?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:9.11.16+dfsg-3~build1","1:9.11.16+dfsg-3~ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libbind9-161","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_version":"1:9.11.16+dfsg-3~ubuntu1","binary_name":"libdns-export1109"},{"binary_version":"1:9.11.16+dfsg-3~ubuntu1","binary_name":"libdns1109"},{"binary_name":"libirs-export161","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_version":"1:9.11.16+dfsg-3~ubuntu1","binary_name":"libirs161"},{"binary_version":"1:9.11.16+dfsg-3~ubuntu1","binary_name":"libisc-export1105"},{"binary_name":"libisc1105","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_name":"libisccc-export161","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_name":"libisccc161","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_version":"1:9.11.16+dfsg-3~ubuntu1","binary_name":"libisccfg-export163"},{"binary_name":"libisccfg163","binary_version":"1:9.11.16+dfsg-3~ubuntu1"},{"binary_name":"liblwres161","binary_version":"1:9.11.16+dfsg-3~ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5946.json"}},{"package":{"name":"bind9","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/bind9?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:9.18.39-0ubuntu0.22.04.4"}]}],"versions":["1:9.16.15-1ubuntu1","1:9.16.15-1ubuntu2","1:9.16.15-1ubuntu3","1:9.18.0-2ubuntu1","1:9.18.0-2ubuntu2","1:9.18.0-2ubuntu3","1:9.18.1-1ubuntu1","1:9.18.1-1ubuntu1.1","1:9.18.1-1ubuntu1.2","1:9.18.1-1ubuntu1.3","1:9.18.12-0ubuntu0.22.04.1","1:9.18.12-0ubuntu0.22.04.2","1:9.18.12-0ubuntu0.22.04.3","1:9.18.18-0ubuntu0.22.04.1","1:9.18.18-0ubuntu0.22.04.2","1:9.18.24-0ubuntu0.22.04.1","1:9.18.28-0ubuntu0.22.04.1","1:9.18.30-0ubuntu0.22.04.1","1:9.18.30-0ubuntu0.22.04.2","1:9.18.39-0ubuntu0.22.04.1","1:9.18.39-0ubuntu0.22.04.2","1:9.18.39-0ubuntu0.22.04.3"],"ecosystem_specific":{"binaries":[{"binary_name":"bind9","binary_version":"1:9.18.39-0ubuntu0.22.04.4"},{"binary_name":"bind9-dnsutils","binary_version":"1:9.18.39-0ubuntu0.22.04.4"},{"binary_name":"bind9-host","binary_version":"1:9.18.39-0ubuntu0.22.04.4"},{"binary_name":"bind9-libs","binary_version":"1:9.18.39-0ubuntu0.22.04.4"},{"binary_name":"bind9-utils","binary_version":"1:9.18.39-0ubuntu0.22.04.4"},{"binary_version":"1:9.18.39-0ubuntu0.22.04.4","binary_name":"bind9utils"},{"binary_version":"1:9.18.39-0ubuntu0.22.04.4","binary_name":"dnsutils"}],"availability":"No 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required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5946.json"}},{"package":{"name":"bind9-libs","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/bind9-libs?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:9.11.19+dfsg-2.1ubuntu1","1:9.11.19+dfsg-2.1ubuntu2","1:9.11.19+dfsg-2.1ubuntu3"],"ecosystem_specific":{"binaries":[{"binary_name":"libbind9-161","binary_version":"1:9.11.19+dfsg-2.1ubuntu3"},{"binary_name":"libdns-export1110","binary_version":"1:9.11.19+dfsg-2.1ubuntu3"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libdns1110"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libirs-export161"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libirs161"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libisc-export1105"},{"binary_name":"libisc1105","binary_version":"1:9.11.19+dfsg-2.1ubuntu3"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libisccc-export161"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libisccc161"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"libisccfg-export163"},{"binary_name":"libisccfg163","binary_version":"1:9.11.19+dfsg-2.1ubuntu3"},{"binary_version":"1:9.11.19+dfsg-2.1ubuntu3","binary_name":"liblwres161"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5946.json"}},{"package":{"name":"bind9","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/bind9?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:9.18.39-0ubuntu0.24.04.5"}]}],"versions":["1:9.18.18-0ubuntu2","1:9.18.21-0ubuntu1","1:9.18.24-0ubuntu3","1:9.18.24-0ubuntu4","1:9.18.24-0ubuntu5","1:9.18.28-0ubuntu0.24.04.1","1:9.18.30-0ubuntu0.24.04.1","1:9.18.30-0ubuntu0.24.04.2","1:9.18.39-0ubuntu0.24.04.1","1:9.18.39-0ubuntu0.24.04.2","1:9.18.39-0ubuntu0.24.04.3"],"ecosystem_specific":{"availability":"No 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