Ruby Rack < 2.2.23 / 3.0.x < 3.1.21 / 3.2 < 3.2.6 Multiple Vulnerabilities

critical Nessus Plugin ID 305959

Synopsis

The remote host has an application installed that is affected by multiple vulnerabilities.

Description

The version of the Rack Ruby library installed on the remote host is prior to 2.2.23, prior to 3.1.21, or prior to 3.2.6.
It is, therefore, affected by multiple vulnerabilities:

- Rack::Utils.get_byte_ranges parses HTTP Range header without limiting the number of individual byte ranges, leading to denial of service (CVE-2026-34826)

- Rack::Static uses simple string prefix check allowing unintended file disclosure (CVE-2026-34785)

- Rack::Utils.select_best_encoding has quadratic time complexity with many wildcard Accept-Encoding entries (CVE-2026-34230)

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

Solution

Upgrade to Rack version 2.2.23, 3.1.21, 3.2.6 or later.

Plugin Details

Severity: Critical

ID: 305959

File Name: ruby_gem_rack_3_2_6.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 4/10/2026

Updated: 4/10/2026

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: 9.4

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

CVSS Score Source: CVE-2026-34785

CVSS v3

Risk Factor: Critical

Base Score: 9.1

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

Vulnerability Information

CPE: cpe:/a:ruby:rack

Required KB Items: Host/ruby/modules/enumerated

Patch Publication Date: 4/2/2026

Vulnerability Publication Date: 4/2/2026

Reference Information

CVE: CVE-2026-26961, CVE-2026-34230, CVE-2026-34763, CVE-2026-34785, CVE-2026-34786, CVE-2026-34826, CVE-2026-34829, CVE-2026-34830, CVE-2026-34831

Detections

Analytics