CVE-2026-33601: Insufficient validation of zonemd record

Published Apr 22, 2026
·
Updated

If you use the zoneToCache function with a malicious authoritative server, an attacker can send a zone that result in a null pointer dereference, caused by a missing consistency check and leading to a denial of service.

Affected Software

3 affected components
PowerDNS recursor>=5.2.0<5.2.9
PowerDNS recursor>=5.3.0<5.3.6
PowerDNS recursor=5.4.0

Event History

Apr 22, 2026
CVE Published
via MITRE·09:37 AM
Data Sourced
via MITRE·09:37 AM
DescriptionSeverityWeakness
Data Sourced
via NVD·10:16 AM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-33601?

CVE-2026-33601 has been classified as a denial of service vulnerability due to a null pointer dereference.

2

How do I fix CVE-2026-33601?

To mitigate CVE-2026-33601, upgrade your PowerDNS recursor to a version that is not affected, specifically later than 5.2.9, 5.3.6, or 5.4.0.

3

What software is affected by CVE-2026-33601?

CVE-2026-33601 affects PowerDNS recursor versions from 5.2.0 to 5.2.9, 5.3.0 to 5.3.6, and specifically 5.4.0.

4

Can CVE-2026-33601 be exploited remotely?

Yes, CVE-2026-33601 can be exploited remotely if a malicious authoritative server is used.

5

What impact does CVE-2026-33601 have on my system?

Exploitation of CVE-2026-33601 can lead to a denial of service, making the affected PowerDNS recursor unavailable.

Contact

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