CVE-2026-26961

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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...

CVE-2026-26961

Rack vulnerable component: Rack::Multipart::Parser extracts multipart boundary from Content-Type using a greedy regex, causing last-boundary selection when multiple boundaries exist. This can allow smuggling of multipart content past upstream validation. Affected versions are before 2.2.23, 3.1.2...

CVE-2026-26961 Rack: Multipart Boundary Parsing Ambiguity allowing WAF Bypass

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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...

CVE-2026-34230

Rack is a modular Ruby web server interface. CVE-2026-34230 describes a denial-of-service risk where Rack::Utils.select_best_encoding enters quadratic time on Accept-Encoding headers with many wildcard entries, enabling an unauthenticated attacker to exhaust CPU in the Rack::Deflater path. The is...

CVE-2026-34230 Rack: Quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

CVE-2026-34230 Rack: Quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

CVE-2026-34230

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

CVE-2026-34230 Rack: Quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

CVE-2026-34230

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

Rack 安全漏洞

Rack is a modular Ruby web server interface developed by Rack authors. Vulnerabilities exist in versions of Rack prior to 2.2.23, 3.1.21, and 3.2.6. These vulnerabilities stem from Rack::Utils.selectbestencoding, which has a quadratic time complexity when processing Accept-Encoding headers...

CVE-2026-34829: Uncontrolled Resource Consumption

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 transfe...

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...

CVE-2026-32762: Interpretation Conflict

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, 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...

CVE-2026-34763: Permissive Regular Expression

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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...

Rack 安全漏洞

Rack is a modular Ruby web server interface developed by Rack authors. Vulnerabilities exist in versions of Rack prior to 2.2.23, 3.1.21, and 3.2.6. These vulnerabilities stem from the use of Stringsize instead of Stringbytesize to set the Content-Length response header in Rack::Filesfail, which...

CVE-2026-34827: Inefficient Algorithmic Complexity

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parserhandlemimehead parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated Stringindex searches combined with...

CVE-2026-34230: Uncontrolled Resource Consumption

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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 respon...

CVE-2026-34831: Improper Handling of Length Parameter Inconsistency

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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...

CVE-2026-26962: Improper Neutralization of CRLF Sequences

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, 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 o...

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...