CVE-2025-46727: 
Ruby vulnerability analysis and mitigation

CVE-2025-46727 affects Rack, a modular Ruby web server interface. The vulnerability was discovered and disclosed on May 7, 2025, impacting versions prior to 2.2.14, 3.0.16, and 3.1.14. The issue lies in the Rack::QueryParser component which parses query strings and application/x-www-form-urlencoded bodies without parameter limits (GitHub Advisory).

The vulnerability stems from Rack::QueryParser's implementation where it iterates over each &-separated key-value pair and adds it to a Hash without enforcing an upper bound on the total number of parameters. This design flaw has been assigned a CVSS v3.1 Base Score of 7.5 (High) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. The vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption) and CWE-770 (Allocation of Resources Without Limits or Throttling) (GitHub Advisory).

The vulnerability enables attackers to trigger denial of service conditions by sending specifically crafted HTTP requests containing hundreds of thousands or more parameters. This can result in memory exhaustion or CPU resource consumption, potentially stalling or crashing the Rack server. The impact persists until the affected worker is restarted (GitHub Advisory).

Several mitigation options are available: 1) Update to patched versions 2.2.14, 3.0.16, or 3.1.14, 2) Implement middleware to enforce maximum query string size or parameter count limits, 3) Use a reverse proxy like Nginx to limit request sizes and reject oversized query strings or bodies. Additionally, limiting request body sizes and query string lengths at the web server or CDN level provides effective mitigation (GitHub Advisory).