What is CVE-2026-41637?

CVE-2026-41637 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 3.7/10. Published 2026-07-22.

How severe is CVE-2026-41637?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in Nlnet Labs Unbound

CVE-2026-41637

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution…

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Nlnet Labs Unbound — versions 1.22.0

Weakness classification (CWE)

CWE-772 — Missing Release of Resource after Effective Lifetime

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-41637?: CVE-2026-41637 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 3.7/10. Published 2026-07-22.
How severe is CVE-2026-41637?: Low severity. CVSS v3 base score is 3.7 out of 10.