CVE-2026-50106
Possible insecure NXDOMAIN for non-existing records under a configured island trust anchor underneath an insecure parent.
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-807 |
| Vendor | nlnet labs |
| Product | unbound |
| Published | Oct 21, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
NLnet Labs / Unbound
0 < 1.26.2
References
Credits
Qifan Zhang (Palo Alto Networks)