What is CVE-2026-56416?

CVE-2026-56416 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Improper Validation of Integrity Check Value. CVSS score: 4.8/10. Published 2026-07-22.

How severe is CVE-2026-56416?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Nlnet Labs Unbound

CVE-2026-56416

In NLnet Labs Unbound up to and including version 1.25.1, when the validator builds the canonical RDATA form for an RRSIG-covered PX/RP/MINFO/SOA RRset, it computes the address of the second embedded domain name as 'datstart + dname_valid(…

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L.

Affected products

Nlnet Labs Unbound — versions 0

Weakness classification (CWE)

CWE-354 — Improper Validation of Integrity Check Value

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-56416?: CVE-2026-56416 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Improper Validation of Integrity Check Value. CVSS score: 4.8/10. Published 2026-07-22.
How severe is CVE-2026-56416?: Medium severity. CVSS v3 base score is 4.8 out of 10.