CVE intelligence

CVE-2026-42258

Vulnerability intelligence

Published May 9, 2026Sources checked Sep 27, 2026

5.3MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-42258 and is rated Medium severity with a CVSS score of 5.3. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

CISA KEVNot listedBased on the latest collected catalog

EPSS1.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-42258?

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.