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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-125111

Rack: Multipart parsing allows DoS via unbounded scan buffer growth

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Status
Published
Published
Updated
Assigning organization
GitHub_M

Description

Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8, Rack::Multipart::Parser can retain parsed data in its internal StringScanner buffer when reads end inside or immediately after multipart headers. An unauthenticated attacker can align many small parts with rack.multipart.buffer_size boundaries so the buffer grows with the request despite per-field, header, and preamble limits, causing a worker to exhaust memory. The attack requires only a well-formed multipart body and affects applications that parse multipart requests. This issue is fixed in versions 2.2.25, 3.1.23, and 3.2.8.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

rack rack

  • < 2.2.25affected
  • >= 3.0, < 3.1.23affected
  • >= 3.2, < 3.2.8affected

References