CVE-2026-50106 (GCVE-0-2026-50106)

Vulnerability from cvelistv5 – Published: 2026-10-21 08:57 – Updated: 2026-10-29 19:06
VLAI
Title
Possible insecure NXDOMAIN for non-existing records under a configured island trust anchor underneath an insecure parent.
Summary
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-29 19:06 UTC
CWE
  • CWE-807 - Reliance on Untrusted Inputs in a Security Decision
Assigner
NLnet Labs CNA
CNA scorecard B 82/100 over 73 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
NLnet Labs Unbound Affected: 0 , < 1.26.2 (semver)
guessed Create a notification for this product.
Date Public
2026-10-21 00:00
Credits
Qifan Zhang (Palo Alto Networks)
Show details on NVD website
To clipboard 

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