CVE-2023-5632 Unconditionally adding an event to the epoll causes excessive CPU consumption

High 7.5 Published 18 Oct 2023 Updated 13 Sep 2024

An attacker can cause excessive CPU consumption and denial of service in Eclipse Mosquitto by establishing connections without sending data.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2023-5632?

CVE-2023-5632 is a high-severity denial of service vulnerability in Eclipse Mosquitto, published on 18 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In Eclipse Mosquito before and including 2.0.5, establishing a connection to the mosquitto server without sending data causes the EPOLLOUT event to be added, which results excessive CPU consumption. This could be used by a malicious actor to perform denial of service type attack. This issue is fixed in 2.0.6

Weakness: CWE-834

Which versions are affected by CVE-2023-5632?

It affects 1 product.

Products include Eclipse Mosquitto.

How do I fix CVE-2023-5632?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-5632 being exploited?

There is no known exploitation of CVE-2023-5632 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2023-5632, GHSA-4jhw-x435-x5f7.