{"id":"DEBIAN-CVE-2026-81634","details":"In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.","modified":"2026-09-24T08:47:35.618111296Z","published":"2026-09-16T09:17:06.210Z","upstream":["CVE-2026-81634"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-81634"}],"affected":[{"package":{"name":"unbound","ecosystem":"Debian:12","purl":"pkg:deb/debian/unbound?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.17.1-2","1.17.1-2+deb12u1","1.17.1-2+deb12u2","1.17.1-2+deb12u3","1.17.1-2+deb12u4","1.17.1-2+loong64","1.18.0-1","1.18.0-2","1.19.1-1","1.19.2-1","1.20.0-1","1.21.1-1","1.22.0-1","1.22.0-2","1.23.1-1","1.24.0-1","1.24.0-2","1.24.1-1","1.24.1-2","1.24.2-1","1.25.0-1","1.25.1-1","1.25.2-1","1.26.0-1","1.26.0-2","1.26.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81634.json"}},{"package":{"name":"unbound","ecosystem":"Debian:13","purl":"pkg:deb/debian/unbound?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.26.1-0+deb13u1"}]}],"versions":["1.22.0-2","1.22.0-2+deb13u1","1.22.0-2+deb13u2","1.22.0-2+deb13u3","1.23.1-1","1.24.0-1","1.24.0-2","1.24.1-1","1.24.1-2","1.24.2-1","1.25.0-1","1.25.1-1","1.25.2-1","1.26.0-1","1.26.0-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81634.json"}},{"package":{"name":"unbound","ecosystem":"Debian:14","purl":"pkg:deb/debian/unbound?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.26.1-1"}]}],"versions":["1.22.0-2","1.23.1-1","1.24.0-1","1.24.0-2","1.24.1-1","1.24.1-2","1.24.2-1","1.25.0-1","1.25.1-1","1.25.2-1","1.26.0-1","1.26.0-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-81634.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}