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Ruby net-imap 0.4.x < 0.4.24 / 0.5.x < 0.5.14 / 0.6.x < 0.6.4 vulnerability

medium Nessus Plugin ID 313277

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Synopsis

The remote host has an application installed that is affected by a computational denial-of-service (DoS) vulnerability.

Description

The version of the net-imap Ruby library installed on the remote host is prior to 0.4.x 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 a computational denial-of-service vulnerability.

A denial of service vulnerability exists when authenticating a connection via SCRAM-SHA1 or SCRAM-SHA256. A malicious server can exploit this by sending an excessively high iteration count value, resulting in significant CPU consumption on the client process. This computational overhead can be used to perform a denial of service attack against the connecting client.

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.

See Also

https://github.com/advisories/GHSA-87pf-fpwv-p7m7

Plugin Details

Severity: Medium

ID: 313277

File Name: ruby_gem_netimap_CVE_2026_42256.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: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-42256

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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

CVSS v4

Risk Factor: Medium

Base Score: 6

Threat Score: 2.3

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/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-2026-42256

IAVB: 2026-B-0117