Inefficient Algorithmic Complexity Affecting rack package, versions >=3.0.0.beta1, <3.1.21>=3.2.0, <3.2.6
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Test your applications- Snyk IDSNYK-RUBY-RACK-15878233
- published3 Apr 2026
- disclosed2 Apr 2026
- creditTaiPhung217
Introduced: 2 Apr 2026
NewCVE-2026-34827 (opens in a new tab)How to fix?
Upgrade rack to version 3.1.21, 3.2.6 or higher.
Overview
rack is 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.
Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity in the handle_mime_head component. An attacker can cause excessive CPU consumption by sending a crafted multipart/form-data request with numerous parts containing long, escape-heavy quoted parameter values.