Critical Security Update for Ruby Packages: Addressing Denial of Service and Command Injection Vulnerabilities
Summary
RLSA-2026:33577: Important: ruby:4.0 security update. Affects rubygem-mysql2 versions < 0:0.5.7-1.module+el9.8.0+40094+ce01217c. Fixed in 0:0.5.7-1.module+el9.8.0+40094+ce01217c. How to fix ↓
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Background
Ruby is an extensible, interpreted, object-oriented scripting language widely used for web development and system management tasks. It offers powerful features for processing text files and managing system operations. However, recent vulnerabilities have been identified in Ruby's net-imap library, which can lead to severe security risks, including Denial of Service and command injection attacks.
Vulnerability Detail
The vulnerabilities in the Ruby net-imap library include a Denial of Service (DoS) via crafted IMAP responses (CVE-2026-42245), IMAP command injection through symbol arguments (CVE-2026-42258), and information disclosure via a man-in-the-middle attack that bypasses TLS (CVE-2026-42246). These vulnerabilities can allow attackers to disrupt service, execute unauthorized commands, or intercept sensitive information, posing significant risks to applications relying on these libraries.
How To Fix
Minimum fixed version
0:0.5.7-1.module+el9.8.0+40094+ce01217c
This is the first release that contains the fix.
sudo dnf update rubygem-mysql2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, consider disabling the use of the net-imap library in your application until the packages can be updated. This may involve modifying your application code to avoid reliance on IMAP functionalities.
Conclusion
The vulnerabilities in Ruby's net-imap library pose significant risks, including Denial of Service and command injection attacks. It is crucial to update the affected packages to their patched versions to mitigate these risks. Utilizing tools like Vulert can help monitor and manage vulnerabilities effectively.
See every vulnerability recorded for rubygem-mysql2 →
FAQ
The main vulnerabilities include Denial of Service via crafted IMAP responses, command injection via symbol arguments, and information disclosure through TLS bypass.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Check your application against the vulnerability using the Vulert playground without needing to sign up.
The CVSS score for these vulnerabilities is 7.4, indicating a high severity level.
If immediate updates are not possible, consider disabling the net-imap library in your application as a temporary workaround.
The Rocky Enterprise Software Foundation and Red Hat have acknowledged these vulnerabilities and provided the necessary updates.
References
Related vulnerabilities
Recent vulnerabilities recorded for rubygem-mysql2.
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