This page tracks the Ubuntu fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-101338 →

UBUNTU-CVE-2026-101338

When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the...

Original description

The description as published by the source.

When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the base64 decoder can write attacker controlled data of unlimited size. 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).

Source: OSV.dev (Open Source Vulnerabilities) OSV