Vulnerability in NLnet Labs NSD

[ Description ]Official description

The BLOCKED access control list items that are evaluated to deny access on the the proxy protocol port can be bypassed completely when connecting over TCP or TLS and sending the query twice on connection that is kept open.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund29 Sep 2026WID-SEC-2026-3663

  OpenBSD: Multiple vulnerabilities Translated from German

  CVE-2026-12245CVE-2026-19401CVE-2026-18664+5 more CVEs

[ References ]References

• www.nlnetlabs.nl/downloads/nsd/CVE-2026-19538.txtvendor-advisory