CVE-2026-42258
5.3 · MEDIUMNet::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby.
Overview
CVE-2026-42258 is a medium-severity vulnerability. It was published on May 9, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical description
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2026-42258?
CVE-2026-42258 is a medium-severity vulnerability. It was published on May 9, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-42258?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-42258?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-42258?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-42258 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.
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