CVE-2026-50248: Nlnetlabs Unbound

Medium severity, CVSS 6.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record (no valid RRSIG required) becomes the zone's XFR primary and can replaces the entire zone/the resolver's entire response policy.

Affected products

• Nlnetlabs Unbound: from 1.7.0, before 1.25.2 (fixed in 1.25.2)

Published 2026-07-22. Last modified 2026-07-24.