{"id":"UBUNTU-CVE-2026-123603","details":"hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients.","modified":"2026-11-10T02:50:13.280650804Z","published":"2026-11-09T00:00:00Z","upstream":["CVE-2026-123603"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-123603"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-123603"},{"type":"REPORT","url":"https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-4jwp-xjwm-333g"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/hickory-dns-missing-ipv4-mapped-ipv6-canonicalization-access-control-bypass"}],"affected":[{"package":{"name":"rust-hickory-proto","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/rust-hickory-proto?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-proto-dev","binary_version":"0.24.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-resolver","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/rust-hickory-resolver?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-resolver-dev","binary_version":"0.24.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-proto","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/rust-hickory-proto?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-6","0.26.1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.26.1-1","binary_name":"librust-hickory-proto-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-recursor","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/rust-hickory-recursor?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.1-1","0.25.2-6"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-recursor-dev","binary_version":"0.25.2-6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-resolver","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/rust-hickory-resolver?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-5","0.26.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-resolver-dev","binary_version":"0.26.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-server","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/rust-hickory-server?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-2","0.26.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-server-dev","binary_version":"0.26.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-proto","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/rust-hickory-proto?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-4.1","0.24.4-6"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-proto-dev","binary_version":"0.24.4-6"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-recursor","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/rust-hickory-recursor?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"librust-hickory-recursor-dev","binary_version":"0.24.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-resolver","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/rust-hickory-resolver?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-1","0.24.4-5"],"ecosystem_specific":{"binaries":[{"binary_version":"0.24.4-5","binary_name":"librust-hickory-resolver-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123603.json"}},{"package":{"name":"rust-hickory-server","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubu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