CVE-2026-42258: Ruby-Lang Net::imap

Medium severity, CVSS 5.3. EPSS: 1.3% chance of exploitation in the next 30 days.

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.

Affected products

• Ruby-Lang Net::imap: before 0.4.24 (fixed in 0.4.24); from 0.5.0, before 0.5.14 (fixed in 0.5.14); from 0.6.0, before 0.6.4 (fixed in 0.6.4)

Published 2026-05-09. Last modified 2026-08-24.