CVE-2026-42257

9.8 CRITICAL
Published: May 09, 2026 Modified: May 18, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/ruby/net-imap/releases/tag/v0.4.24
Source: security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.5.14
Source: security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.6.4
Source: security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg
Source: security-advisories@github.com
Mitigation Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
0.0%
5th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

ruby-lang