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CVE-2026-34826GHSA-X8CG-FQ8G-MXFX

Rack: Unbounded Range Count in get_byte_ranges Enables DoS

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.2.23, 3.1.21, 3.2.6
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • rack rack

    fixed in 2.2.23; From 3.0.0.beta1 · fixed in 3.1.21; From 3.2.0 · fixed in 3.2.6

  • rackRubyGems

    fixed in 2.2.23

  • rackRubyGems

    From 3.0.0.beta1 · fixed in 3.1.21

  • rackRubyGems

    From 3.2.0 · fixed in 3.2.6

References 1

GitHub · rack/rack