CVE-2009-3602: Nlnetlabs Unbound

High severity, CVSS 7.5. EPSS: 3% chance of exploitation in the next 30 days.

Unbound before 1.3.4 does not properly verify signatures for NSEC3 records, which allows remote attackers to cause secure delegations to be downgraded via DNS spoofing or other DNS-related attacks in conjunction with crafted delegation responses.

Affected products

• Nlnetlabs Unbound: up to and including 1.3.3; version 0.0 only; version 0.1 only; version 0.2 only; version 0.3 only; version 0.4 only; …

Published 2009-10-13. Last modified 2026-06-16.