Oracle Linux: CVE-2025-61919: ELSA-2025-19512: pcs security update (IMPORTANT) (Multiple Advisories)

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`).
A memory-exhaustion vulnerability exists in Rack when parsing application/x-www-form-urlencoded request bodies. Rack::Request#POST reads the entire request body into memory without enforcing a maximum length or cap. Attackers can exploit this by sending large form submissions, potentially causing denial of service (DoS) through memory exhaustion. Even with configured parsing limits, the issue occurs before those limits are enforced, allowing unbounded memory allocation proportional to request size.