CVE-2026-50106 When NLnet Labs Unbound up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-50106?
CVE-2026-50106 is a medium-severity vulnerability in NLnet Labs Unbound, published on 21 Oct 2026.
Official description
When NLnet Labs Unbound up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for an island-of-security zone whose parent is provably insecure under the root chain, a malicious actor who can deliver one forged NXDOMAIN response for a name inside the island, with the NSEC/SOA RRSIG 'SignerName' set to the insecure parent, tricks Unbound's validator to use the root trust anchor instead, and consecutively the insecure parent, thus causing that record to be treated as insecure and denying existence for records in the trust island.
Weakness: CWE-807
Which versions are affected by CVE-2026-50106?
How do I fix CVE-2026-50106?
Upgrade to a fixed version.
Is CVE-2026-50106 being exploited?
There is no known exploitation of CVE-2026-50106 in the wild and no public exploit code.
Sources
Also known as AZL-110531, DEBIAN-CVE-2026-50106, ECHO-2c39-6a3d-2a23, GHSA-pj55-6fvm-845h, UBUNTU-CVE-2026-50106.