{"id":"CVE-2026-81634","published":"2026-09-16T09:17:06.210","lastModified":"2026-09-16T19:41:10.423","description":"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.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-122"],"vendors":[],"products":[],"references":[{"url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-81634.txt","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}