CVE-2026-34826CWE-400CWE-770

Rack: Unbounded Range Count in get_byte_ranges Enables DoS

Medium · published April 2, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
38.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00460 · 38.9th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-04-02T16:45Z
EPSS history
Timeline
  • 02 APR 16:45Z
    Rack: Unbounded Range Count in get_byte_ranges Enables DoS
    cvelistv5