{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81634","assignerOrgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","state":"PUBLISHED","assignerShortName":"NLnet Labs","dateReserved":"2026-09-07T14:06:21.967Z","datePublished":"2026-09-16T08:30:15.428Z","dateUpdated":"2026-09-16T14:32:38.842Z"},"containers":{"cna":{"title":"Possible heap buffer overflow during DNSSEC canonicalization","datePublic":"2026-09-16T00:00:00.000Z","affected":[{"vendor":"NLnet Labs","product":"Unbound","versions":[{"version":"0","status":"affected","lessThan":"1.26.1","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}}],"problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-122","description":"CWE-122: Heap-based Buffer Overflow","type":"CWE"}]}],"solutions":[{"lang":"en","value":"This issue is fixed starting with version 1.26.1"}],"timeline":[{"time":"2026-07-31T00:00:00.000Z","lang":"en","value":"Issue reported by Vlatko Kosturjak"},{"time":"2026-08-03T00:00:00.000Z","lang":"en","value":"NLnet Labs shares patch"},{"time":"2026-08-04T00:00:00.000Z","lang":"en","value":"Vlatko Kosturjak verifies patch"},{"time":"2026-09-16T00:00:00.000Z","lang":"en","value":"Fixes released with version 1.26.1"}],"credits":[{"lang":"en","value":"Vlatko Kosturjak (Marlink Cyber)","type":"finder"}],"references":[{"url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-81634.txt","tags":["vendor-advisory"]}],"providerMetadata":{"orgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","shortName":"NLnet Labs","dateUpdated":"2026-09-16T08:30:15.428Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T14:32:31.803030Z","id":"CVE-2026-81634","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-16T14:32:38.842Z"}}]}}