CVE-2026-42257

medium

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, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

References

https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg

https://github.com/ruby/net-imap/releases/tag/v0.6.4

https://github.com/ruby/net-imap/releases/tag/v0.5.14

https://github.com/ruby/net-imap/releases/tag/v0.4.24

Details

Source: Mitre, NVD

Published: 2026-05-09

Updated: 2026-05-18

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 5.8

Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00021