CVE-2026-33594Network attack vector

Denial of service via retained DoH queries

Published Apr 22, 2026 · Updated Apr 22, 2026

Resource exhaustion in PowerDNS DNSdist 1.9.0 through 1.9.12 and 2.0.0 through 2.0.3 allows remote attackers to interrupt service. The outgoing DoH path queues client queries routed to an overloaded backend in a connection-scoped buffer and does not release them until that connection ends. Outgoing DoH must be enabled and its backend overloaded; sustained unauthenticated query traffic can exhaust memory, with no reported system compromise.

CVSS severity5.3
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in PowerDNS DNSdist 1.9.0 through 1.9.12 and 2.0.0 through 2.0.3 allows remote attackers to interrupt service. The outgoing DoH path queues client queries routed to an overloaded backend in a connection-scoped buffer and does not release them until that connection ends. Outgoing DoH must be enabled and its backend overloaded; sustained unauthenticated query traffic can exhaust memory, with no reported system compromise.

The record

CVE
CVE-2026-33594
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
PowerDNS
Product
DNSdist
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.9.0 <1.9.13
  2. Affected versionversion=2.0.0 <2.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PowerDNS · DNSdistversion=1.9.0 <1.9.13; version=2.0.0 <2.0.4

Published CVSS scores

5.3Open-XchangeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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