What is CVE-2026-42955?

CVE-2026-42955 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Operation on a Resource after Expiration or Release. CVSS score: 3.7/10. Published 2026-07-22.

How severe is CVE-2026-42955?

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

Vulnerability in Nlnet Labs Unbound

CVE-2026-42955

In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window by up to one cached TTL co…

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:L/A:N.

Affected products

Nlnet Labs Unbound — versions 1.16.2

Weakness classification (CWE)

CWE-672 — Operation on a Resource after Expiration or Release

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-42955?: CVE-2026-42955 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Operation on a Resource after Expiration or Release. CVSS score: 3.7/10. Published 2026-07-22.
How severe is CVE-2026-42955?: Low severity. CVSS v3 base score is 3.7 out of 10.