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`).
Advisories
Source ID Title
Debian DLA Debian DLA DLA-4357-1 ruby-rack security update
Debian DSA Debian DSA DSA-6048-1 ruby-rack security update
Github GHSA Github GHSA GHSA-6xw4-3v39-52mm Rack is vulnerable to a memory-exhaustion DoS through unbounded URL-encoded body parsing
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 03 Nov 2025 19:30:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*

Mon, 20 Oct 2025 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Rack
Rack rack
Vendors & Products Rack
Rack rack

Tue, 14 Oct 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Fri, 10 Oct 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 10 Oct 2025 19:30:00 +0000

Type Values Removed Values Added
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
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-10-10T20:48:20.240Z

Reserved: 2025-10-03T22:21:59.615Z

Link: CVE-2025-61919

cve-icon Vulnrichment

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

cve-icon NVD

Status : Analyzed

Published: 2025-10-10T20:15:37.730

Modified: 2025-11-03T19:28:04.420

Link: CVE-2025-61919

cve-icon Redhat

Severity : Important

Publid Date: 2025-10-10T19:22:42Z

Links: CVE-2025-61919 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-10-20T16:17:09Z