Is CVE-2026-40211 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40211 being exploited in the wild.

How severe is CVE-2026-40211?

Medium severity, with a CVSS score of 5.3, published 25 June 2026.

Which products and versions are affected?

Powerdns Dnsdist 1.9.0 to 1.9.14, 2.0.0 to 2.0.6.

Is there a fix for CVE-2026-40211?

A patch was published on 2026-06-25: Fixed in versions 1.9.15 and 2.0.7 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-40211 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-40211?

Check whether you run Powerdns Dnsdist at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40211: PowerDNS DNSdist denial of service in DNS over HTTP/3

CVE-2026-40211 · Severity: medium · CVSS 5.3 · Published 2026-06-25

PowerDNS DNSdist, a load balancer used to manage and protect DNS traffic, is vulnerable to a denial-of-service attack when handling specific web-based DNS queries. An attacker can send specially crafted requests that cause the system to consume memory without releasing it immediately. If enough of these requests are sent, the system may run out of memory and stop responding to legitimate DNS traffic, potentially disrupting internet connectivity for users.

Technologies: Powerdns Dnsdist. Vendors: Powerdns.

Quick answers

Is CVE-2026-40211 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40211 being exploited in the wild.
How severe is CVE-2026-40211?: Medium severity, with a CVSS score of 5.3, published 25 June 2026.
Which products and versions are affected?: Powerdns Dnsdist 1.9.0 to 1.9.14, 2.0.0 to 2.0.6.
Is there a fix for CVE-2026-40211?: A patch was published on 2026-06-25: Fixed in versions 1.9.15 and 2.0.7 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-40211 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-40211?: Check whether you run Powerdns Dnsdist at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability in the DNS over HTTP/3 (DoH3) implementation of PowerDNS DNSdist allows an unauthenticated remote attacker to trigger an exception by sending crafted queries. This exception prevents internal buffers from being freed immediately; instead, they remain allocated until the underlying QUIC connection is terminated. By opening a large number of concurrent DoH3 streams, an attacker can exhaust available system memory, resulting in an out-of-memory (OOM) condition and a denial of service. The issue is rooted in the DoH3 processing logic within dnsdist-crypto.cc and is fixed in versions 1.9.15 and 2.0.7.

Affected products

PowerDNS DNSdist 1.9.0 to 1.9.14, 2.0.0 to 2.0.6

Timeline

2026-04-09: disclosed: Discovery date
2026-06-25: advisory: Public advisory released by PowerDNS
2026-06-25: patched: Fixed in versions 1.9.15 and 2.0.7

References

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