What is CVE-2026-50248?

CVE-2026-50248 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-07-22.

How severe is CVE-2026-50248?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Nlnet Labs Unbound

CVE-2026-50248

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname…

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L.

Affected products

Nlnet Labs Unbound — versions 1.7.0

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

sep@nlnetlabs.nl (vendor-advisory)

Frequently asked questions

What is CVE-2026-50248?: CVE-2026-50248 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-07-22.
How severe is CVE-2026-50248?: Medium severity. CVSS v3 base score is 6.5 out of 10.