CVE-2026-42257
net-imap: Command Injection via "raw" arguments to multiple commands
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.
INFO
Published Date :
May 9, 2026, 8:16 p.m.
Last Modified :
May 18, 2026, 5:59 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Net::IMAP to version 0.4.24 or later.
- Update Net::IMAP to version 0.5.14 or later.
- Update Net::IMAP to version 0.6.4 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42257.
| URL | Resource |
|---|---|
| https://github.com/ruby/net-imap/releases/tag/v0.4.24 | Release Notes |
| https://github.com/ruby/net-imap/releases/tag/v0.5.14 | Release Notes |
| https://github.com/ruby/net-imap/releases/tag/v0.6.4 | Release Notes |
| https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42257 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42257
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42257 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42257 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:ruby-lang:net::imap:*:*:*:*:*:ruby:*:* versions up to (excluding) 0.4.24 *cpe:2.3:a:ruby-lang:net::imap:*:*:*:*:*:ruby:*:* versions from (including) 0.5.0 up to (excluding) 0.5.14 *cpe:2.3:a:ruby-lang:net::imap:*:*:*:*:*:ruby:*:* versions from (including) 0.6.0 up to (excluding) 0.6.4 Added Reference Type GitHub, Inc.: https://github.com/ruby/net-imap/releases/tag/v0.4.24 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/ruby/net-imap/releases/tag/v0.5.14 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/ruby/net-imap/releases/tag/v0.6.4 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
May. 09, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-77 Added CWE CWE-93 Added Reference https://github.com/ruby/net-imap/releases/tag/v0.4.24 Added Reference https://github.com/ruby/net-imap/releases/tag/v0.5.14 Added Reference https://github.com/ruby/net-imap/releases/tag/v0.6.4 Added Reference https://github.com/ruby/net-imap/security/advisories/GHSA-hm49-wcqc-g2xg