Allocation of Resources Without Limits or Throttling Affecting rack package, versions >=3.2.0, <3.2.3>=3.0.0, <3.1.18<2.2.20
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published12 Oct 2025
- disclosed10 Oct 2025
- creditTomoya Yamashita
Introduced: 10 Oct 2025
NewCVE-2025-61919 (opens in a new tab)How to fix?
Upgrade rack to version 3.2.3, 3.1.18, 2.2.20 or higher.
Overview
rack is a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call.
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the Rack::Request#POST process. An attacker can exhaust system memory by sending large application/x-www-form-urlencoded request bodies, causing application slowdowns or termination by the operating system due to out-of-memory conditions. This occurs before any parameter parsing or configured parsing limits are enforced, allowing unbounded memory allocation proportional to the request size and concurrency.
Workaround
This vulnerability can be mitigated by enforcing strict maximum body size at the proxy or web server layer, such as configuring Nginx client_max_body_size or Apache LimitRequestBody.