Incorrect Behavior Order: Validate Before Canonicalize

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 singl...

CVE-2026-34786

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Staticapplicablerules evaluates several headerrules types against the raw URL-encoded PATHINFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a...

CVE-2026-34786

Vulnerability summary: CVE-2026-34786 affects Rack’s static file serving. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable_rules compares header_rules against the raw URL-encoded PATH_INFO while the file path is decoded for serving. This can allow a URL-encoded path variant to...