CVE-2026-40209

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.

CVSS Vector

References

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