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`).
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade pcsUpgrade pcs-snmp | Nov 21, 2025 | Nov 4, 2025 |
| Debian | — | Upgrade ruby-rack | Nov 4, 2025 | Nov 4, 2025 |
| Oracle_linux | — | Upgrade cockpit-ha-clusterUpgrade pcsUpgrade pcs-snmp | Nov 5, 2025 | Oct 10, 2025 |
| Redhat_linux | — | Upgrade pcs-debuginfoUpgrade pcs-snmpUpgrade cockpit-ha-clusterUpgrade pcs | Nov 5, 2025 | Oct 10, 2025 |
| Rocky_linux | — | Upgrade pcsUpgrade pcs-snmp | Feb 5, 2026 | Nov 21, 2025 |
| Ubuntu | — | Upgrade ruby-rack (Ubuntu Pro)Upgrade ruby-rack | Jan 16, 2026 | Jan 14, 2026 |
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