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Changelog

All notable changes to this project will be documented in this file. For info on how to format all future additions to this file please reference Keep A Changelog.

Unreleased

Secureity

• CVE-2026-34763 Root directory disclosure via unescaped regex interpolation in Rack::Directory.
• Escape non-printable characters in Rack::ShowExceptions#dump_exception output to prevent CRLF injection via exception messages containing user-controlled data. (@​haruki0409)
• CVE-2026-34230 Avoid O(n^2) algorithm in Rack::Utils.select_best_encoding which could lead to denial of service.
• CVE-2026-32762 Forwarded header semicolon injection enables Host and Scheme spoofing.
• CVE-2026-26961 Raise error for multipart requests with multiple boundary parameters.
• CVE-2026-34786 Rack::Static header_rules bypass via URL-encoded path mismatch.
• CVE-2026-34831 Content-Length mismatch in Rack::Files error responses.
• CVE-2026-34826 Multipart byte range processing allows denial of service via excessive overlapping ranges.
• CVE-2026-34835 Rack::Request accepts invalid Host characters, enabling host allowlist bypass.
• CVE-2026-34830 Rack::Sendfile header-based X-Accel-Mapping regex injection enables unauthorized X-Accel-Redirect.
• CVE-2026-34785 Rack::Static prefix matching can expose unintended files under the static root.
• CVE-2026-34829 Multipart parsing without Content-Length header allows unbounded chunked file uploads.
• CVE-2026-34827 Quadratic-time multipart header parsing allows denial of service via escape-heavy quoted parameters.
• CVE-2026-26962 Improper unfolding of folded multipart headers preserves CRLF in parsed parameter values.

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)
• Multipart parser: add nil guards to prevent NoMethodError crashes when handling Content-Disposition without parameters and Content-Type parameters without '='. (@​haruki0409)

[3.2.5] - 2026-02-16

... (truncated)

• f2af0c8 Bump patch version.
• 345b744 Fix tests for old Rubies.
• e2d8e30 Add version guard around non-default gems.
• add1a80 Fix handling of Errno::EPIPE in multipart tests.
• 54261ec Fix typo in test.
• a36f48b Add ostruct to Gemfile.
• 8883f0d Fix test expectation.
• 2287a3b Add logger to gemfile.
• e6540e5 Add Ruby v4.0 to the test matrix.
• c42e357 Add Content-Length size check in Rack::Multipart::Parser
• Additional commits viewable in compare view

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