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 request bodies can therefore be buffered completely into process memory before parsing, leading to denial of service (DoS) through memory exhaustion. Users should upgrade to Rack version 2.2.20, 3.1.18, or 3.2.3, anu of which enforces form parameter limits using `query_parser.bytesize_limit`, preventing unbounded reads of `application/x-www-form-urlencoded` bodies. Additionally, enforce strict maximum body size at the proxy or web server layer (e.g., Nginx `client_max_body_size`, Apache `LimitRequestBody`).
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History
Fri, 10 Oct 2025 21:15:00 +0000
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Fri, 10 Oct 2025 19:30:00 +0000
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Description | 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 request bodies can therefore be buffered completely into process memory before parsing, leading to denial of service (DoS) through memory exhaustion. Users should upgrade to Rack version 2.2.20, 3.1.18, or 3.2.3, anu of which enforces form parameter limits using `query_parser.bytesize_limit`, preventing unbounded reads of `application/x-www-form-urlencoded` bodies. Additionally, enforce strict maximum body size at the proxy or web server layer (e.g., Nginx `client_max_body_size`, Apache `LimitRequestBody`). | |
Title | Rack is vulnerable to a memory-exhaustion DoS through unbounded URL-encoded body parsing | |
Weaknesses | CWE-400 | |
References |
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Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2025-10-10T20:48:20.240Z
Reserved: 2025-10-03T22:21:59.615Z
Link: CVE-2025-61919

Updated: 2025-10-10T20:48:15.513Z

Status : Received
Published: 2025-10-10T20:15:37.730
Modified: 2025-10-10T20:15:37.730
Link: CVE-2025-61919

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