CVE-2026-42257

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.

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-77 CWE-77

CWE-93 CWE-93

References

Other References

https://github.com/ruby/net-imap/releases/tag/v0.4.24 https://github.com/ruby/net-imap/releases/tag/v0.5.14 https://github.com/ruby/net-imap/releases/tag/v0.6.4 https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg

Frequently Asked Questions

What is CVE-2026-42257? +

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.

How do I check if I'm vulnerable to CVE-2026-42257? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-42453

Termix is a web-based server management platform with SSH terminal, tunneling, and file editing capabilities. Prior to version 2.1.0, the …

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 …

CVE-2023-5878

Honeywell OneWireless Wireless Device Manager (WDM) for the following versions R310.x, R320.x, R321.x, R322.1, R322.2, R323.x, R330.1 contains a command …

CVE-2025-46735

Terraform WinDNS Provider allows users to manage their Windows DNS server resources through Terraform. A security issue has been found …

CVE-2025-4009

The Evertz SDVN 3080ipx-10G is a High Bandwidth Ethernet Switching Fabric for Video Application. This device exposes a web management …

CVE-2024-4999

A vulnerability in the web-based management interface of multiple Ligowave devices could allow an authenticated remote attacker to execute arbitrary …