CVE-2026-34830 (Medium) detected in rack-3.2.3.gem

Vulnerable Library - rack-3.2.3.gem

Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call.

Library home page: https://rubygems.org/gems/rack-3.2.3.gem

Sample Path to Dependency File: /Gemfile.lock

Path to vulnerable library: /vendor/cache/rack-3.2.3.gem

Dependency Hierarchy:

• openid_connect-1.4.2.gem (Root Library)
  • rack-oauth2-1.21.3.gem
    • ❌ rack-3.2.3.gem (Vulnerable Library)

Found in base branch: master

Vulnerability Details

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex metacharacters and control the generated X-Accel-Redirect response header. In deployments using Rack::Sendfile with x-accel-redirect, this can allow an attacker to cause nginx to serve unintended files from configured internal locations. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Publish Date: 2026-04-02

URL: CVE-2026-34830

CVSS 3 Score Details (5.9)

Base Score Metrics:

• Exploitability Metrics:
  • Attack Vector: Network
  • Attack Complexity: High
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
• Impact Metrics:
  • Confidentiality Impact: High
  • Integrity Impact: None
  • Availability Impact: None

Suggested Fix

Type: Upgrade version

Origin: https://github.com/advisories/GHSA-qv7j-4883-hwh7

Release Date: 2026-04-02

Fix Resolution: rack - 3.2.6,rack - 2.2.23,rack - 3.1.21