Critical Security Flaw in mod_md Package: Important Update Required
Summary
ALSA-2025:23738: Important: mod_md security update. Affects mod_md versions < 1:2.4.26-4.el10_1. Fixed in 1:2.4.26-4.el10_1. How to fix ↓
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Background
The mod_md package is an essential module for the Apache HTTP Server that automates the management of domain properties for virtual hosts. It utilizes the ACME protocol to facilitate automated certificate provisioning, ensuring that SSL/TLS certificates are correctly configured and renewed for managed domains. This functionality is crucial for maintaining secure communications over the web, but it also introduces potential vulnerabilities if not properly managed.
Vulnerability Detail
The vulnerability identified as CVE-2025-55753 in the mod_md package relates to unintended retry intervals during the certificate provisioning process. This flaw can lead to denial of service conditions, where legitimate requests may be delayed or dropped due to excessive retries. The issue stems from improper handling of retry logic, which could be exploited by attackers to disrupt service availability or to perform other malicious actions.
How To Fix
Minimum fixed version
1:2.4.26-4.el10_1
This is the first release that contains the fix.
sudo dnf update mod_mdTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can manually adjust the retry intervals in their configuration files to mitigate the impact of this vulnerability until the package is updated. However, it is highly recommended to apply the official patch as soon as possible for a permanent solution.
Conclusion
The mod_md package has a critical vulnerability that requires immediate attention. By updating to the latest version, users can protect their systems from potential exploitation. Regular monitoring and updates are essential for maintaining security in open-source software.
See every vulnerability recorded for mod_md →
FAQ
mod_md is an Apache HTTP Server module that automates the management of SSL/TLS certificates for domains using the ACME protocol.
CVE-2025-55753 refers to a security vulnerability in the mod_md package that involves unintended retry intervals during certificate provisioning.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
The risks include potential denial of service conditions, where legitimate requests may be delayed or dropped, impacting service availability.
It is recommended to regularly check for updates and apply them promptly to ensure that your software is secure and up-to-date.
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