CVE-2026-33259Network attack vector

Service crash via concurrent RPZ transfers

Published Apr 22, 2026 · Updated Apr 22, 2026

Use-after-free in the RPZ module of PowerDNS Recursor allows remote authenticated users to crash the service via concurrent zone transfers. The RPZ transfer path modifies shared policy-zone data during overlapping updates, leaving stale references that the recursor later dereferences. Reachability requires primary-based RPZ transfers and a malfunctioning or attacker-controlled configured provider; triggering corrupts policy data or terminates the recursor.

CVSS severity5.0
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the RPZ module of PowerDNS Recursor allows remote authenticated users to crash the service via concurrent zone transfers. The RPZ transfer path modifies shared policy-zone data during overlapping updates, leaving stale references that the recursor later dereferences. Reachability requires primary-based RPZ transfers and a malfunctioning or attacker-controlled configured provider; triggering corrupts policy data or terminates the recursor.

The record

CVE
CVE-2026-33259
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
PowerDNS
Product
PowerDNS Recursor
Classifications
CWE-416, T1499.004
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

5.0Open-XchangeCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

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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