CVE-2026-81642: CWE-122: Heap-based Buffer Overflow in NLnet Labs Unbound
In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.
CVE-2026-81642: CWE-122: Heap-based Buffer Overflow in NLnet Labs Unbound
Description
In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.
CVSS v4.0
Score 9.1critical
Affected software
NLnet Labs
Unbound
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NLnet Labs
- Date Reserved
- 2026-09-07T14:06:21.956Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6aaa578955bf5e2cf540b1fb
Added to database: 09/16/2026, 08:47:05 UTC
Last updated: 09/16/2026, 08:47:05 UTC
Views: 1
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