What is CVE-2026-54478?

CVE-2026-54478 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Authentication Bypass by Spoofing. CVSS score: 3.7/10. Published 2026-07-22.

How severe is CVE-2026-54478?

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

Vulnerability in Nlnet Labs Unbound

CVE-2026-54478

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXY…

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 1.18.0

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-54478?: CVE-2026-54478 is a low-severity vulnerability in Nlnet Labs Unbound, classified under Authentication Bypass by Spoofing. CVSS score: 3.7/10. Published 2026-07-22.
How severe is CVE-2026-54478?: Low severity. CVSS v3 base score is 3.7 out of 10.