What is CVE-2026-56444?

CVE-2026-56444 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 5.9/10. Published 2026-07-22.

How severe is CVE-2026-56444?

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

Vulnerability in Nlnet Labs Unbound

CVE-2026-56444

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during th…

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 1.20.0

Weakness classification (CWE)

CWE-772 — Missing Release of Resource after Effective Lifetime

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-56444?: CVE-2026-56444 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 5.9/10. Published 2026-07-22.
How severe is CVE-2026-56444?: Medium severity. CVSS v3 base score is 5.9 out of 10.