6.5

CVE-2026-50106: nlnet labs unbound

CVSS: 6.5v3.1MediumReceived
Published 21-10-2026Last modified 21-10-2026
Open JSON

Vulnerability summary

CVE-2026-50106 is a medium (CVSS 6.5) vulnerability in nlnet labs unbound. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.5% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.19%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 21-10-2026
    PublishedVulnerability first disclosed.

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.19%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

21-10-202621-10-2026
EPSS score
0.19%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Nlnet labs1 product

1 vendor · 1 product

References

1 links