Improper Handling of Length Parameter Inconsistency Affecting ruby-rack package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.03% (8th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-DEBIANUNSTABLE-RUBYRACK-15922758
  • published7 Apr 2026
  • disclosed2 Apr 2026

Introduced: 2 Apr 2026

NewCVE-2026-34831  (opens in a new tab)
CWE-130  (opens in a new tab)
CWE-135  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable ruby-rack.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ruby-rack package and not the ruby-rack package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters. This results in incorrect HTTP response framing and may cause response desynchronization in deployments that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

CVSS Base Scores

version 3.1