by Kastro
Paper/Archive/CVE-2026-81642

CVE-2026-81642

NLnet Labs Unbound — Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

EPSS 1.0%CVSS 9.8
critical.is priorityof 100
42
CVSS 9.8 (NVD)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 61.7.617 × 2012.3No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Unbound< 1.26.11.26.1CNA

Scores by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NLnet Labs (CNA)9.1CVSS: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
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorynlnetlabs.nl/downloads/unbound/CVE-2026-81642.txt