CRLF Injection CVE-2026-42258 in Ruby Net::IMAP <0.6.4 via Symbol args
CVE-2026-42258 Published on May 9, 2026

net-imap: Command Injection via unvalidated Symbol inputs
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.

NVD

Vulnerability Analysis

CVE-2026-42258 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a high impact on integrity, and no impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
LOW
Integrity Impact:
HIGH
Availability Impact:
NONE

Weakness Types

What is a Command Injection Vulnerability?

The software constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

CVE-2026-42258 has been classified to as a Command Injection vulnerability or weakness.

What is a CRLF Injection Vulnerability?

The software uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

CVE-2026-42258 has been classified to as a CRLF Injection vulnerability or weakness.


Products Associated with CVE-2026-42258

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Red Hat Hummingbird
 
Red Hat 3scale Amp
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Openshift Ai
 
Red Hat Openshift
 
Red Hat Openshift Devspaces
 
Red Hat Rhel Eus
 
Red Hat Rhel E4s
 
Red Hat Rhel Tus
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel Els
 

Affected Versions

ruby net-imap: Red Hat Enterprise Linux Server (v. 7 ELS): Red Hat Enterprise Linux Server Optional (v. 7 ELS): Red Hat Enterprise Linux AppStream EUS (v. 10.0): Red Hat Enterprise Linux AppStream (v. 10): Red Hat Enterprise Linux AppStream (v. 8): Red Hat Enterprise Linux AppStream AUS (v.8.4): Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4): Red Hat Enterprise Linux AppStream AUS (v.8.6): Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6): Red Hat Enterprise Linux AppStream E4S (v.8.8): Red Hat Enterprise Linux AppStream TUS (v.8.8): Red Hat Enterprise Linux AppStream E4S (v.9.2): Red Hat Enterprise Linux AppStream E4S (v.9.4): Red Hat Enterprise Linux AppStream EUS (v.9.6): Red Hat Enterprise Linux AppStream (v. 9): Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0): Red Hat Enterprise Linux CodeReady Linux Builder (v. 10): Red Hat CodeReady Linux Builder EUS (v.9.6): Red Hat Enterprise Linux CodeReady Linux Builder (v. 9): Red Hat Hardened Images: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift Container Platform 4: Red Hat Enterprise Linux 6: Red Hat OpenShift Dev Spaces: Red Hat 3scale API Management Platform 2:

Exploit Probability

EPSS
0.94%
Percentile
56.19%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.