Ruby net-imap < 0.4.24 / 0.5.x < 0.5.14 / 0.6.x < 0.6.4 Multiple Vulnerabilities

medium Nessus Plugin ID 313278

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Synopsis

The remote host has a module installed that is affected by multiple vulnerabilities.

Description

The version of the net-imap Ruby library installed on the remote host is prior to 0.4.24, 0.5.x prior to 0.5.14, or 0.6.x prior to 0.6.4. It is, therefore, affected by multiple vulnerabilities.

- The Net::IMAP::ResponseReader component is affected by a quadratic time complexity flaw when parsing large server responses containing numerous string literals. A malicious IMAP server can exploit this issue via crafted responses to exhaust client CPU resources and cause a denial of service. (CVE-2026-42245)

- Several Net::IMAP commands fail to properly validate or escape raw string arguments. If these strings incorporate user-controlled data, an attacker can use injected CRLF sequences to execute arbitrary IMAP commands. (CVE-2026-42257)

- Symbol arguments passed to IMAP commands are susceptible to CRLF/IMAP command injection. This vulnerability allows for the injection of arbitrary IMAP commands via specially crafted Symbol arguments. (CVE-2026-42258)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to net-imap version 0.4.24, 0.5.14, or 0.6.4.

Plugin Details

Severity: Medium

ID: 313278

File Name: ruby_gem_netimap_CVE_2026_42245_42257_42258.nasl

Version: 1.3

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 5/8/2026

Updated: 5/19/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-42258

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 5.8

Threat Score: 1.9

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/a:ruby:net-imap

Required KB Items: Host/ruby/modules/enumerated

Exploit Ease: No known exploits are available

Patch Publication Date: 4/23/2026

Vulnerability Publication Date: 4/23/2026

Reference Information

CVE: CVE-2026-42245, CVE-2026-42257, CVE-2026-42258

IAVB: 2026-B-0117

Detections

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