This page tracks the Debian fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-40211 →

DEBIAN-CVE-2026-40211

An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will b...

Original description

The description as published by the source.

An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Affected packages

Debian:12 dnsdist

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Debian:13 dnsdist

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-0+deb13u1"}]}]

Debian:14 dnsdist

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.0-1"}]}]

References

advisory security-tracker.debian.org