CVE-2026-50106CWE-807

CVE-2026-50106

Medium · published October 21, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
8.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
CVSS v4.0
Not supplied
EPSS
0.00194 · 8.6th percentile
Weakness
CWE-807 · Reliance on Untrusted Inputs in a Security Decision
Published
2026-10-21T13:17Z
References (1)
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-50106.txt · [email protected]
EPSS history
Timeline
  • 22 OCT 03:33Z
    EPSS moved — → 0%
    epss
  • 21 OCT 08:57Z
    Possible insecure NXDOMAIN for non-existing records under a configured island trust anchor underneath an insecure parent.
    cvelistv5
  • 21 OCT 08:57Z
    Possible insecure NXDOMAIN for non-existing records under a configured island trust anchor underneath an insecure parent.
    cvelistv5