CVEvulnerability

CVE-2026-81634

7.5 HIGH Published 2026-09-16 Modified 2026-09-23 Official page ↗
Status
Analyzed
Published
2026-09-16
Last modified
2026-09-23
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-122

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.

Affected configurations

• nlnetlabs unbound (< 1.26.1)

Related

Weakness · CWE (1)

  • CWE-122 Heap-based Buffer Overflow weakness

References