Vulnerability in NLnet Labs NSD

[ Description ]Official description

If NSD is configured as secondary for a zone, the primary of that zone can crash NSD with an AXFR containing a DNS message with a special crafted SVCB RR with an rdata size of 65512, that let's an (uint16_t) variable that is used to allocate space needed for the RR wrap (because total size > 65535), causing a heap overflow. The attacker can perform a controlled (RCE class) head write of up to 65509 bytes

[ 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-2026-12244.txtvendor-advisory