Heap overflow with multiple NSID, COOKIE, PADDING EDNS options

...

CVE-2026-42944

A flaw was found in Unbound, a Domain Name System DNS resolver. A remote attacker could trigger a heap overflow by sending specially crafted DNS reply packets. This occurs when Unbound attempts to encode multiple Name Server Identifier NSID or Extension Mechanisms for DNS EDNS Cookie options, or...

CVE-2026-42944

NLnet Labs Unbound 1.14.0–1.25.0 is affected by a heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in replies. The vulnerability requires the options (nsid, answer-cookie, pad-responses) to be enabled, and a querier can trigger the overflow by attaching...

CVE-2026-42944

NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options 'nsid', 'answer-cookie', 'pad-responses' default need to be enabl...