Unbound 1.26.1 Patches Critical DNSSEC Validator Flaw CVE-2026-81642 Enabling Remote Code Execution
NLnet Labs has released Unbound 1.26.1 to address CVE-2026-81642, a critical vulnerability in the DNSSEC validator that can cause service crashes and potential remote code execution. The flaw affects all versions up to and including 1.26.0 and is triggered when validating a malicious DNS zone. It resides in the handling of DNSKEY records, where a buffer overflow can occur during DNS response processing. The vulnerability carries a CVSS 4.0 score of 9.1 with a network attack vector, no privileges required, and no user interaction needed. Exploitation requires an attacker to control a malicious DNS zone that the resolver queries, which can lead to denial of service or RCE in the worst case. The update also includes fixes for eight additional security issues, including CVE-2026-82717 and CVE-2026-81634, both involving heap corruption.
HispasecSep 18, 2026Translated from Spanish