CVE-2026-33256: Unbounded memory allocation by internal web server

Published Apr 22, 2026
·
Updated

An attacker can send a web request that causes unlimited memory allocation in the internal web server, leading to a denial of service. The internal web server is disabled by default.

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-2026-33256?

CVE-2026-33256 has a severity rating that indicates it can lead to denial of service due to unbounded memory allocation.

2

How do I fix CVE-2026-33256?

To address CVE-2026-33256, ensure the internal web server is disabled if not in use, or upgrade to a fixed version of PowerDNS recursor.

3

What software versions are affected by CVE-2026-33256?

CVE-2026-33256 affects PowerDNS recursor versions from 5.2.0 to 5.2.9, versions from 5.3.0 to 5.3.6, and 5.4.0.

4

Can CVE-2026-33256 impact my system?

Yes, CVE-2026-33256 can cause system instability and denial of service if exploited through unbounded memory allocation.

5

Is the internal web server enabled by default in PowerDNS recursor with CVE-2026-33256?

No, the internal web server is disabled by default in PowerDNS recursor, which mitigates the risk posed by CVE-2026-33256.

Contact

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