PT-2026-29817 · Rack+3 · Rack+3
Th4S1S
·
Published
2026-04-02
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Updated
2026-05-13
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CVE-2026-34829
CVSS v3.1
7.5
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Rack versions prior to 2.2.23, 3.1.21, and 3.2.6
Description
Rack's
Rack::Multipart::Parser does not limit the size of multipart uploads when a Content-Length header is not present, such as with HTTP chunked transfer encoding. Specifically, when processing multipart/form-data requests without a Content-Length header, the parser continues reading until the end of the stream without a size limit. For file parts, the uploaded data is written directly to a temporary file without being constrained by the in-memory upload limit. This allows an unauthenticated attacker to stream an arbitrarily large file upload, potentially consuming unbounded disk space and causing a denial of service. The parser applies BoundedIO only when content length is not nil:io = BoundedIO.new(io, content length) if content lengthRecommendations
Update to Rack version 2.2.23 or later.
Update to Rack version 3.1.21 or later.
Update to Rack version 3.2.6 or later.
Exploit
Fix
DoS
Allocation of Resources Without Limits
Resource Exhaustion
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Related Identifiers
Affected Products
Linuxmint
Rack
Red Os
Ubuntu