PT-2026-29844

Name of the Vulnerable Software and Affected Versions Rack versions 3.0.0.beta1 through 3.1.20 and 3.2.0 through 3.2.5 Description The Rack web server interface is susceptible to a header parsing issue within Rack::Utils.forwarded values. The component incorrectly parses the RFC 7239 Forwarded...

PT-2026-29815

Name of the Vulnerable Software and Affected Versions Rack versions prior to 2.2.23, 3.1.21, and 3.2.6 Description The Rack::Utils.get byte ranges function parses the HTTP Range header without limiting the number of individual byte ranges. While a previous fix for CVE-2024-26141 prevents ranges...

PT-2026-29918

Summary Rack::Filesfail sets the Content-Length response header using Stringsize instead of Stringbytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the...

PT-2026-29915

Summary Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or...

PT-2026-29913

Summary Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, , and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be...

PT-2026-29910

Summary Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENT LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size...

PT-2026-29909

Summary Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, , or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem pa...

PT-2026-29919

Summary Rack::Staticapplicable rules evaluates several header rules types against the raw URL-encoded PATH INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the heade...

PT-2026-29819

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::Filesfail function incorrectly calculates the Content-Length response header using Stringsize instead of Stringbytesize. This occurs when the response body contains...

PT-2026-29810

Name of the Vulnerable Software and Affected Versions Rack versions prior to 2.2.23, 3.1.21, and 3.2.6 Description Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If the root path contains regex metacharacters su...

Rack's multipart byte range processing allows denial of service via excessive overlapping ranges

Summary Rack::Utils.getbyteranges 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...

Rack's multipart parsing without Content-Length header allows unbounded chunked file uploads

Summary Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENTLENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size...

Rack's multipart header parsing allows Denial of Service via escape-heavy quoted parameters

Summary Rack::Multipart::Parserhandlemimehead parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated Stringindex searches combined with Stringslice! prefix deletion. For escape-heavy quoted values, this causes super-linear processing. An unauthenticat...

Rack has a root directory disclosure via unescaped regex interpolation in Rack::Directory

Summary Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, , or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem pa...

Rack's improper unfolding of folded multipart headers preserves CRLF in parsed parameter values

Summary Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result,...

Rack::Sendfile header-based X-Accel-Mapping regex injection enables unauthorized X-Accel-Redirect

Summary Rack::Sendfilemapaccelpath interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex...

Rack's greedy multipart boundary parsing can cause parser differentials and WAF bypass.

Summary Rack::Multipart::Parser extracts the boundary parameter from multipart/form-data using a greedy regular expression. When a Content-Type header contains multiple boundary parameters, Rack selects the last one rather than the first. In deployments where an upstream proxy, WAF, or intermedia...

Rack has Content-Length mismatch in Rack::Files error responses

Summary Rack::Filesfail sets the Content-Length response header using Stringsize instead of Stringbytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the...

Rack - Forwarded Header semicolon injection enables Host and Scheme spoofing

Summary Rack::Utils.forwardedvalues parses the RFC 7239 Forwarded header by splitting on semicolons before handling quoted-string values. Because quoted values may legally contain semicolons, a header such as: http Forwarded: for="127.0.0.1;host=evil.com;proto=https" can be interpreted by Rack as...

Rack has quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header

Summary Rack::Utils.selectbestencoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted...