What is CVE-2026-40211?

CVE-2026-40211 is a medium-severity vulnerability in Powerdns Dnsdist, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-06-25.

How severe is CVE-2026-40211?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Resource exhaustion in Powerdns Dnsdist

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 be freed at the end of the QUIC connection, but on some setups it might be possible to ope…

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Powerdns Dnsdist — versions 1.9.0, 2.0.0

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

security@open-xchange.com

Frequently asked questions

What is CVE-2026-40211?: CVE-2026-40211 is a medium-severity vulnerability in Powerdns Dnsdist, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-06-25.
How severe is CVE-2026-40211?: Medium severity. CVSS v3 base score is 5.3 out of 10.