CVE-2026-50248 PUBLISHED

BOGUS configured primary hostname accepted for XFR in auth/rpz zones

Assigner: NLnet Labs
Reserved: 22.06.2026 Published: 22.07.2026 Updated: 22.07.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L
CVSS Score: 6.5

Product Status

Vendor NLnet Labs
Product Unbound
Versions Default: unaffected
  • affected from 1.7.0 to 1.25.2 (excl.)

Solutions

This issue is fixed starting with version 1.25.2

Credits

  • Qifan Zhang (Palo Alto Networks) finder

References

Problem Types

  • CWE-345: Insufficient Verification of Data Authenticity CWE