CVE-2026-50248

Medium

Description

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's A/AAAA record (no valid RRSIG required) becomes the zone's XFR primary and can replaces the entire zone/the resolver's entire response policy.

SeverityMedium

CVSS6.5

Exploit probability—

ProductNlnetlabs Unbound

PublishedJul 22, 2026

First seenJul 22, 2026

Weakness typeCWE-345CWE-345

How to fix

Update

nlnetlabs unbound1.25.2 or later

Vendor advisories

nlnetlabs.nl/downloads/unbound/CVE-2026-50248.txt

Affected products

Product	Affected versions	Fixed in
nlnetlabs unbound	1.7.0 ≤ v < 1.25.2	1.25.2

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.