CVE-2026-34835 - Medium Severity Vulnerability
Vulnerable Library - rack-3.1.16.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-3.1.16.gem
Path to dependency file: /Gemfile.lock
Path to vulnerable library: /vendor/cache/rack-3.1.16.gem
Dependency Hierarchy:
- manageiq-style-1.3.3.gem (Root Library)
- rubocop-rails-2.32.0.gem
- ❌ rack-3.1.16.gem (Vulnerable Library)
Found in base branch: master
Vulnerability Details
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6.
Publish Date: 2026-04-02
URL: CVE-2026-34835
CVSS 3 Score Details (4.8)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: GHSA-g2pf-xv49-m2h5
Release Date: 2026-04-02
Fix Resolution: rack - 3.2.6,rack - 3.1.21
Step up your Open Source Security Game with Mend here
CVE-2026-34835 - Medium Severity Vulnerability
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-3.1.16.gem
Path to dependency file: /Gemfile.lock
Path to vulnerable library: /vendor/cache/rack-3.1.16.gem
Dependency Hierarchy:
Found in base branch: master
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6.
Publish Date: 2026-04-02
URL: CVE-2026-34835
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: None
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: GHSA-g2pf-xv49-m2h5
Release Date: 2026-04-02
Fix Resolution: rack - 3.2.6,rack - 3.1.21
Step up your Open Source Security Game with Mend here