CVE-2026-50251 Attacker supplied '0.0.0.0'/'::' glue triggers defensive full-cache flush

In NLnet Labs Unbound up to and including version 1.25.1, when 'unwanted-reply-threshold' is enabled set to any value greater than zero, glue records of 0.0.0.0/::0 can short-circuit Unbound, on systems that can direct such traffic, by issuing DNS queries and receiving seemingly unwanted replies...

CVE-2026-50251

This entry describes a vulnerability in NLnet Labs Unbound (≤ 1.25.1) where enabling unwanted-reply-threshold (>0) allows a malicious delegation returning in-bailiwick glue 0.0.0.0/::0 to cause repeated, seemingly unwanted replies. The mismatch between 0.0.0.0/::0 and the local 127.0.0.1 persp...