CVE-2026-33256
Received Received - Intake
Unrestricted Memory Allocation in Open-Xchange Web Server Causes DoS

Publication date: 2026-04-22

Last updated on: 2026-04-27

Assigner: Open-Xchange

Description
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.
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Meta Information
Published
2026-04-22
Last Modified
2026-04-27
Generated
2026-06-16
AI Q&A
2026-04-22
EPSS Evaluated
2026-06-15
NVD
CVE-2026-33256
EUVD
EUVD-2026-24719
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
powerdns recursor From 5.2.0 (inc) to 5.2.9 (exc)
powerdns recursor From 5.3.0 (inc) to 5.3.6 (exc)
powerdns recursor 5.4.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
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Executive Summary

This vulnerability allows an attacker to send a specially crafted web request to the internal web server that triggers unlimited memory allocation. This excessive memory consumption can cause the server to become unresponsive or crash, resulting in a denial of service condition.

It is important to note that the internal web server is disabled by default, which may reduce the likelihood of exploitation.

Impact Analysis

The primary impact of this vulnerability is a denial of service (DoS) condition. An attacker exploiting this issue can cause the internal web server to consume unlimited memory, potentially leading to system instability or crashes.

Since the internal web server is disabled by default, the risk depends on whether it has been enabled in your environment.

Mitigation Strategies

The internal web server is disabled by default, so ensuring it remains disabled is an immediate mitigation step.

Avoid enabling the internal web server unless necessary, as it is vulnerable to an attacker sending web requests that cause unlimited memory allocation leading to denial of service.

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