{"id":"DEBIAN-CVE-2026-123596","details":"Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancestor-delegation NSEC records as proof of nonexistence for names below the zone cut. An on-path attacker, rogue parent nameserver, or attacker winning a port and TXID race can deliver one forged NXDOMAIN response built from genuinely signed parent NSEC records, causing authenticated denial of existing child-zone names cached for the negative TTL.","modified":"2026-11-08T16:00:06.731882047Z","published":"2026-11-08T02:16:54.020Z","upstream":["CVE-2026-123596"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-123596"}],"affected":[{"package":{"name":"rust-hickory-net","ecosystem":"Debian:14","purl":"pkg:deb/debian/rust-hickory-net?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.26.3-1"}]}],"versions":["0.26.1-1","0.26.1-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-123596.json"}},{"package":{"name":"rust-hickory-proto","ecosystem":"Debian:13","purl":"pkg:deb/debian/rust-hickory-proto?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-2","0.24.4-3","0.24.4-4","0.24.4-4.1","0.24.4-5","0.24.4-6","0.25.2-1","0.25.2-2","0.25.2-3","0.26.1-1","0.26.3-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-123596.json"}},{"package":{"name":"rust-hickory-proto","ecosystem":"Debian:14","purl":"pkg:deb/debian/rust-hickory-proto?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.24.4-2","0.24.4-3","0.24.4-4","0.24.4-4.1","0.24.4-5","0.24.4-6","0.25.2-1","0.25.2-2","0.25.2-3","0.26.1-1","0.26.3-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-123596.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}