CVE-2026-40209 Affecting dnsdist package, versions <2.1.0-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.29% (22nd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-DNSDIST-17496133
  • published26 Jun 2026
  • disclosed25 Jun 2026

Introduced: 25 Jun 2026

CVE-2026-40209  (opens in a new tab)

How to fix?

Upgrade Debian:unstable dnsdist to version 2.1.0-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dnsdist package and not the dnsdist package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.

CVSS Base Scores

version 3.1