CVE-2023-25824 mod_gnutls contains Infinite Loop on request read timeout

High 7.5 Published 23 Feb 2023 Updated 10 Mar 2025

An attacker can cause a denial of service by triggering an infinite loop in mod_gnutls during TLS read timeouts, consuming CPU resources.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-25824?

CVE-2023-25824 is a high-severity denial of service vulnerability in airtower-luna mod_gnutls, published on 23 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Mod_gnutls is a TLS module for Apache HTTPD based on GnuTLS. Versions from 0.9.0 to 0.12.0 (including) did not properly fail blocking read operations on TLS connections when the transport hit timeouts. Instead it entered an endless loop retrying the read operation, consuming CPU resources. This could be exploited for denial of service attacks. If trace level logging was enabled, it would also produce an excessive amount of log output during the loop, consuming disk space. The problem has been fixed in commit d7eec4e598158ab6a98bf505354e84352f9715ec, please update to version 0.12.1. There are no workarounds, users who cannot update should apply the errno fix detailed in the security advisory.

Weakness: CWE-835

Which versions are affected by CVE-2023-25824?

It affects 1 product.

Products include Mod Gnutls Project Mod Gnutls.

How do I fix CVE-2023-25824?

No fix has been published for CVE-2023-25824 yet. Limit exposure of the affected software until one is available.

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-2023-25824 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-25824 exists.

Sources

Also known as GHSA-6cfv-fvgm-7pc8, UBUNTU-CVE-2023-25824.