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Changelog

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Unreleased

Security

• CVE-2025-61780 Improper handling of headers in Rack::Sendfile may allow proxy bypass.
• CVE-2025-61919 Unbounded read in Rack::Request form parsing can lead to memory exhaustion.
• CVE-2026-25500 XSS injection via malicious filename in Rack::Directory.
• CVE-2026-22860 Directory traversal via root prefix bypass in Rack::Directory.

SPEC Changes

• Define rack.response_finished callback arguments more strictly. (#2365, @​skipkayhil)

Added

• Add Rack::Files#assign_headers to allow overriding how the configured file headers are set. (#2377, @​codergeek121)
• Add support for rack.response_finished to Rack::TempfileReaper. (#2363, @​skipkayhil)
• Add support for streaming bodies when using Rack::Events. (#2375, @​unflxw)
• Add deflaters option to Rack::Deflater to enable custom compression algorithms like zstd. (#2168, @​alexanderadam)
• Add Rack::Request#prefetch? for identifying requests with Sec-Purpose: prefetch header set. (#2405, @​glaszig)
• Add rack.request.trusted_proxy environment key to indicate whether the request is coming from a trusted proxy.

Changed

• Raise before exceeding a part limit, not after. (#2362, @​matthew-puku)
• Rack::Deflater now uses a fixed GZip mtime value. (#2372, @​bensheldon)
• Multipart parser drops support for RFC 2231 filename* parameter (prohibited by RFC 7578) and now properly handles UTF-8 encoded filenames via percent-encoding and direct UTF-8 bytes. (#2398, @​wtn)
• The query parser now raises Rack::QueryParser::IncompatibleEncodingError if we try to parse params that are not ASCII compatible. (#2416, @​bquorning)

Fixed

• Multipart parser: limit MIME header size check to the unread buffer region to avoid false multipart mime part header too large errors when previously read data accumulates in the scan buffer. (#2392, @​alpaca-tc, @​willnet, @​krororo)
• Fix Rack::MockResponse#body when the body is a Proc. (#2420, #2423, @​tavianator, [@​ioquatix])

[3.2.4] - 2025年11月03日

Fixed

• Multipart parser: limit MIME header size check to the unread buffer region to avoid false multipart mime part header too large errors when previously read data accumulates in the scan buffer. (#2392, @​alpaca-tc, @​willnet, @​krororo)

• bb5f355 Bump patch version.
• f9bde3b Prevent directory traversal via root prefix bypass.
• 93a68f5 XSS injection via malicious filename in Rack::Directory.
• 3b8b0d2 Fix MockResponse#body when the body is a Proc (#2420)
• 4c24539 Bump patch version.
• 3ba5e4f Allow Multipart head to span read boundary. (#2392)
• See full diff in compare view

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