What is CVE-2026-40622?

CVE-2026-40622 is a high-severity vulnerability in Nlnet Labs Unbound, classified under Origin Validation Error. CVSS score: 7.5/10. Published 2026-05-20.

How severe is CVE-2026-40622?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Nlnet Labs Unbound

CVE-2026-40622

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost doma…

EPSS: 0.000 (5.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Nlnet Labs Unbound — versions 1.16.2
Nlnetlabs Unbound

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

sep@nlnetlabs.nl (vendor-advisory, Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-40622?: CVE-2026-40622 is a high-severity vulnerability in Nlnet Labs Unbound, classified under Origin Validation Error. CVSS score: 7.5/10. Published 2026-05-20.
How severe is CVE-2026-40622?: High severity. CVSS v3 base score is 7.5 out of 10.