CVE-2025-61770

Rack is a modular Ruby web server interface. In versions prior to 2.2.19, 3.1.17, and 3.2.2, `Rack::Multipart::Parser` buffers the entire multipart preamble (bytes before the first boundary) in memory without any size limit. A client can send a large preamble followed by a valid boundary, causing significant memory use and potential process termination due to out-of-memory (OOM) conditions. Remote attackers can trigger large transient memory spikes by including a long preamble in multipart/form-data requests. The impact scales with allowed request sizes and concurrency, potentially causing worker crashes or severe slowdown due to garbage collection. Versions 2.2.19, 3.1.17, and 3.2.2 enforce a preamble size limit (e.g., 16 KiB) or discard preamble data entirely. Workarounds include limiting total request body size at the proxy or web server level and monitoring memory and set per-process limits to prevent OOM conditions.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*

History

10 Oct 2025, 16:44

Type Values Removed Values Added
References () https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181e - () https://github.com/rack/rack/commit/589127f4ac8b5cf11cf88fb0cd116ffed4d2181e - Patch
References () https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29e - () https://github.com/rack/rack/commit/d869fed663b113b95a74ad53e1b5cae6ab31f29e - Patch
References () https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fd - () https://github.com/rack/rack/commit/e08f78c656c9394d6737c022bde087e0f33336fd - Patch
References () https://github.com/rack/rack/security/advisories/GHSA-p543-xpfm-54cp - () https://github.com/rack/rack/security/advisories/GHSA-p543-xpfm-54cp - Vendor Advisory, Mitigation
CPE cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
First Time Rack
Rack rack

07 Oct 2025, 15:16

Type Values Removed Values Added
New CVE

Information

Published : 2025-10-07 15:16

Updated : 2025-10-10 16:44


NVD link : CVE-2025-61770

Mitre link : CVE-2025-61770

CVE.ORG link : CVE-2025-61770


JSON object : View

Products Affected

rack

  • rack
CWE
CWE-400

Uncontrolled Resource Consumption