CVE-2026-42257

CWE-77Published: May 9, 2026· Updated: May 13, 2026

5.8

CVSS v3.1

EPSS:0.02%probability of exploitation in 30 daysPercentile:6.1th

Official 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.

NVD Source

Technical Analysis

CVE-2026-42257 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation does not require any privileges, though user interaction (P) is needed, which slightly reduces the risk of mass automated attacks.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges Req.None

User InteractionP

ScopeX

Impact

Confidentiality

Integrity

Availability

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/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