PowerDNS DNSdist up to 1.9.14/2.0.6 denial of service

Summaryinfo

A vulnerability described as problematic has been identified in PowerDNS DNSdist up to 1.9.14/2.0.6. Impacted is an unknown function of the component DNS Handler. Executing a manipulation can lead to denial of service. This vulnerability is registered as CVE-2026-40211. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in PowerDNS DNSdist up to 1.9.14/2.0.6. It has been declared as problematic. This vulnerability affects an unknown code block of the component DNS Handler. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

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 open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

The weakness was published by Mehtab Zafar. The advisory is shared for download at dnsdist.org. This vulnerability was named CVE-2026-40211 since 04/10/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 1.9.15 or 2.0.7 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-39350). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Domain Name Software

Vendor

• PowerDNS

Name

• DNSdist

Version

• 1.9.0
• 1.9.1
• 1.9.2
• 1.9.3
• 1.9.4
• 1.9.5
• 1.9.6
• 1.9.7
• 1.9.8
• 1.9.9
• 1.9.10
• 1.9.11
• 1.9.12
• 1.9.13
• 1.9.14
• 2.0.0
• 2.0.1
• 2.0.2
• 2.0.3
• 2.0.4
• 2.0.5
• 2.0.6

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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