CVE-2026-40209

MEDIUM

PowerDNS DNSdist - Denial of Service via IXFR Queries

Title source: rule

Description

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.

References (1)

Core 1

Core References

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html

Scores

CVSS v3 5.3

EPSS 0.0029

EPSS Percentile 21.3%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-772

Status published

Products (2)

PowerDNS/DNSdist 1.9.0 - 1.9.15

PowerDNS/DNSdist 2.0.0 - 2.0.7

Published Jun 25, 2026

Tracked Since Jun 25, 2026