CVE-2026-34826
Rack: Unbounded Range Count in get_byte_ranges Enables DoS
Description
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.
CVSS Vector Breakdown
AV:NAttack VectorAC:LAttack ComplexityPR:NPrivileges RequiredUI:NUser InteractionS:UScopeC:NConfidentialityI:NIntegrityA:LAvailabilityWeaknesses
Affected Products
Exploitability
Attack Graph
Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.
MITRE ATT&CK
1 techniqueReferences
Timeline
Unlock Complete Vulnerability Intelligence
Get the full picture for CVE-2026-34826 and every CVE in our database. Create a free account — no credit card required.
Create Free Account