CVE-2026-42004

An attacker can send a crafted EDNS OPT record that will be ignored by DNSdist’s filtering rules, but will be rewritten as a valid OPT record when EDNS Client Subnet is inserted, causing the backend to see the EDNS options that DNSdist did not filter...

unbound: Heap overflow and crash with multiple nsid, cookie, padding EDNS options

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-2026-41292

NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data...