What is CVE-2026-44621?

CVE-2026-44621 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 5.9/10. Published 2026-07-22.

How severe is CVE-2026-44621?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Vulnerability in Nlnet Labs Unbound

CVE-2026-44621

With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'lib…

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Nlnet Labs Unbound — versions 0

Weakness classification (CWE)

CWE-754 — Improper Check for Unusual or Exceptional Conditions

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-44621?: CVE-2026-44621 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 5.9/10. Published 2026-07-22.
How severe is CVE-2026-44621?: Medium severity. CVSS v3 base score is 5.9 out of 10.