CVE-2026-33594 PUBLISHED

Outgoing DoH excessive memory allocation

Assigner: OX
Reserved: 23.03.2026 Published: 22.04.2026 Updated: 22.04.2026

A client can trigger excessive memory allocation by generating a lot of queries that are routed to an overloaded DoH backend, causing queries to accumulate into a buffer that will not be released until the end of the connection.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 5.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	PowerDNS
Product	DNSdist
Versions	Default: unaffected affected from 1.9.0 to 1.9.13 (excl.) affected from 2.0.0 to 2.0.4 (excl.)

Credits

Mehtab Zafar finder

References

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html

Problem Types

Allocation of Resources Without Limits or Throttling CWE