CVE-2026-81642criticalCWE-122

CVE-2026-81642: critical vulnerability in NLnet Labs Unbound

Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

Published

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48Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 9.1epss 1.0%
from disclosure to weapon2 days
Published on NVDSep 16
1st PoC+2d
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Red
Affected products
NLnet Labs · Unbound
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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