CVE-2026-33601Network attack vector

Service crash via inconsistent ZONEMD record handling

Published Apr 22, 2026 · Updated Apr 22, 2026

NULL pointer dereference in PowerDNS Recursor allows remote authenticated users to crash the service via a crafted ZONEMD record. The ZoneMD module's zoneToCache path omits a consistency check and dereferences a null pointer while processing the transferred record. Exploitation requires zoneToCache to use a malicious authoritative server; the documented impact is a service crash without system compromise.

CVSS severity4.4
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in PowerDNS Recursor allows remote authenticated users to crash the service via a crafted ZONEMD record. The ZoneMD module's zoneToCache path omits a consistency check and dereferences a null pointer while processing the transferred record. Exploitation requires zoneToCache to use a malicious authoritative server; the documented impact is a service crash without system compromise.

The record

CVE
CVE-2026-33601
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
PowerDNS
Product
PowerDNS Recursor
Classifications
CWE-476, T1499
Attack vector
network
Privileges
authenticated

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=5.2.0 <5.2.9
  2. Affected versionversion=5.3.0 <5.3.6
  3. Affected versionversion=5.4.0 <5.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PowerDNS · PowerDNS Recursorversion=5.2.0 <5.2.9; version=5.3.0 <5.3.6; version=5.4.0 <5.4.1

Published CVSS scores

4.4Open-XchangeCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
4.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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