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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-04-22

Last Modified

2026-04-27

Generated

2026-07-06

AI Q&A

2026-04-22

EPSS Evaluated

2026-07-05

NVD

CVE-2026-33256

EUVD

EUVD-2026-24719

Affected Vendors & Products

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

KEV

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.

Attack-Flow Graph

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.

Hi! I’m here to help you understand CVE-2026-33256. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70