CVE-2026-34826 PUBLISHED CVSS 5.3 MEDIUM

Reported by GitHub_M · Published April 2, 2026

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.

Risk Scores

CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected Products

VendorProductVersions
rackrack< 2.2.23, >= 3.0.0.beta1, < 3.1.21, >= 3.2.0, < 3.2.6
rackrack>= 3.2.0, < 3.2.6, *, *

Timeline

References

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