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 part...
Vendor
rack vulnerabilities
46 published CVES affecting rack, from public sources (CVE.org, NVD, CISA KEV, FIRST EPSS, OSV).
- Total
- 46
- Critical
- 1
- High
- 24
- Medium
- 20
- Low
- 1
- Unscored
- 0
- CISA KEV
- 0
Products
Latest rack CVEs
Newest publication first · page 1 of 2
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HighCVSS 7.5 EPSS 0.37%
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CVE-2026-125110 Rack: Rack::Static header_rules bypass via dot-segment normalization mismatch
PublishedMediumCVSS 5.3 EPSS 0.25%Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8, Rack::Static serves a path after Utils.clean_path_info normalization but evaluates header_rules against a path that is only URL-decoded. An unauthenticated attacker can request a known file through r...
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MediumCVSS 4.8 EPSS 0.22%
Rack is a modular Ruby web server interface. From 3.0 until 3.1.23 and 3.2.8, Rack::Request#host_with_port, #base_url, and #url can return an attacker-controlled invalid authority from Host, X-Forwarded-Host, or Forwarded: host= verbatim. Applications without an independent host...
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LowCVSS 3.7 EPSS 0.24%
Rack is a modular Ruby web server interface. Prior to 2.2.25, 3.1.23, and 3.2.8, Rack::Multipart::Parser.parse_boundary can skip a leading empty or quoted boundary parameter in a multipart Content-Type header and accept a later parameter. Rack can therefore parse a request body w...
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CriticalCVSS 9.3 EPSS 0.27% PoC
Rack::Session is a session management implementation for Rack. From 2.0.0 to before 2.1.2, Rack::Session::Cookie incorrectly handles decryption failures when configured with secrets:. If cookie decryption fails, the implementation falls back to a default decoder instead of reject...
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MediumCVSS 6.5 EPSS 0.24% PoC
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 s...
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MediumCVSS 6.5 EPSS 0.20% PoC
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::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and...
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HighCVSS 7.5 EPSS 0.49% PoC
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::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated String#index searches...
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CVE-2026-32762 Rack: Forwarded Header semicolon injection enables Host and Scheme spoofing
PublishedMediumCVSS 6.5 EPSS 0.19% PoCRack 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.forwarded_values parses the RFC 7239 Forwarded header by splitting on semicolons before handling quoted-string values. Because quoted values may legally...
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HighCVSS 7.5 EPSS 0.24% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path 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 head...
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CVE-2026-34829 Rack: Denial of Service via Unbounded Multipart File Upload Without Content-Length
PublishedHighCVSS 7.5 EPSS 0.38% PoCRack 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 CONTENT_LENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HT...
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HighCVSS 7.5 EPSS 0.40% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges 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 c...
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MediumCVSS 5.3 EPSS 0.20% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable_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 re...
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HighCVSS 7.5 EPSS 0.39% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, 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...
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CVE-2026-34763 Rack: Rack::Directory info disclosure and DoS via unescaped regex interpolation
PublishedMediumCVSS 5.3 EPSS 0.25% PoCRack 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 .,...
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MediumCVSS 6.5 EPSS 0.15% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length...
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MediumCVSS 5.3 EPSS 0.26% PoC
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 sel...
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HighCVSS 7.5 EPSS 0.45% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Defl...
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MediumCVSS 5.4 EPSS 0.27% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.22, 3.1.20, and 3.2.5, Rack::Directory generates an HTML directory index where each file entry is rendered as a clickable link. If a file exists on disk whose basename starts with the javascript: scheme (e.g. java...
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HighCVSS 7.5 EPSS 0.76% PoC
Rack is a modular Ruby web server interface. Prior to versions 2.2.22, 3.1.20, and 3.2.5, Rack::Directory’s path check used a string prefix match on the expanded path. A request like /../root_example/ can escape the configured root if the target path starts with the root string,...
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HighCVSS 7.5 EPSS 0.65%
Rack is a modular Ruby web server interface. Prior to versions 2.2.20, 3.1.18, and 3.2.3, Rack::Request#POST reads the entire request body into memory for Content-Type: application/x-www-form-urlencoded, calling rack.input.read(nil) without enforcing a length or cap. Large reques...
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MediumCVSS 5.3 EPSS 0.55%
Rack is a modular Ruby web server interface. Prior to versions 2.2.20, 3.1.18, and 3.2.3, a possible information disclosure vulnerability existed in Rack::Sendfile when running behind a proxy that supports x-sendfile headers (such as Nginx). Specially crafted headers could cause...
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HighCVSS 7.5 EPSS 0.93%
Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, Rack::Multipart::Parser can accumulate unbounded data when a multipart part’s header block never terminates with the required blank line (CRLFCRLF). The parser keeps appending incoming by...
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HighCVSS 7.5 EPSS 0.56%
Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, ``Rack::Multipart::Parserstores non-file form fields (parts without afilename) entirely in memory as Ruby Stringobjects. A single large text field in a multipart/form-data request (hundre...
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CVE-2025-61770 Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)
PublishedHighCVSS 7.5 EPSS 0.93%Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, Rack::Multipart::Parser buffers the entire multipart preamble (bytes before the first boundary) in memory without any size limit. A client can send a large preamble followed by a valid bo...
Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.