What’s Vulnerable › Vulnerabilities
CVE-2026-81642: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.0% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-16 · updated 2026-09-22
- Weakness: CWE-122
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.
Affected products
- NLnet Labs Unbound: before 1.26.1 — fixed in 1.26.1
How to fix
Upgrade to a fixed version: NLnet Labs Unbound 1.26.1. Check the vendor advisory for mitigations.
References
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