Vulnerability in NLnet Labs NSD

[ Description ]Official description

When base64 data is split up in pieces, of 3 character or less, tokens were incorrectly calculated to produce 0 bytes. This enables attackers to overwrite the stack with up to 64K of attacker controlled data. Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system).

[ 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-Bund19 Oct 2026WID-SEC-2026-4044

  OpenBSD: Multiple vulnerabilities Translated from German

  CVE-2026-101341CVE-2026-101337CVE-2026-101338+1 more CVEs

[ References ]References

• www.nlnetlabs.nl/downloads/nsd/CVE-2026-101337.txt