Improper Handling of Length Parameter Inconsistency Affecting rack package, versions <2.2.23>=3.0.0.beta1, <3.1.21>=3.2.0, <3.2.6
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Test your applications- Snyk IDSNYK-RUBY-RACK-15878237
- published3 Apr 2026
- disclosed2 Apr 2026
- creditOblivionsage
Introduced: 2 Apr 2026
NewCVE-2026-34831 (opens in a new tab)How to fix?
Upgrade rack to version 2.2.23, 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 Improper Handling of Length Parameter Inconsistency via the Rack::Files#fail component. An attacker can cause incorrect HTTP response framing and potential response desynchronization by requesting a non-existent path containing percent-encoded UTF-8 characters, which leads to a mismatch between the declared and actual Content-Length values.