REDHAT-BUG-2454488: High severity Rack Rack vulnerability
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser only wraps the request body in a BoundedIO when CONTENTLENGTH is present. When a multipart/form-data request is sent without a Content-Length header, such as with HTTP chunked transfer encoding, multipart parsing continues until end-of-stream with no total size limit. For file parts, the uploaded body is written directly to a temporary file on disk rather than being constrained by the buffered in-memory upload limit. An unauthenticated attacker can therefore stream an arbitrarily large multipart file upload and consume unbounded disk space. This results in a denial of service condition for Rack applications that accept multipart form data. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Rackto a version that resolves this vulnerability.Fixed in 2.2.23 - Upgrade
Upgrade
Rackto a version that resolves this vulnerability.Fixed in 3.1.21 - Upgrade
Upgrade
Rackto a version that resolves this vulnerability.Fixed in 3.2.6
Event History
Frequently Asked Questions
What is the severity of REDHAT-BUG-2454488?
The severity of REDHAT-BUG-2454488 is rated as high with a score of 7.
How do I fix REDHAT-BUG-2454488?
To fix REDHAT-BUG-2454488, update Rack to versions 2.2.23, 3.1.21, or 3.2.6 or later.
What impact does REDHAT-BUG-2454488 have on my application?
REDHAT-BUG-2454488 can lead to potential issues with handling multipart/form-data requests effectively when the Content-Length header is missing.
Is REDHAT-BUG-2454488 a critical vulnerability?
While REDHAT-BUG-2454488 is deemed high severity, whether it is critical depends on your application's use of multipart/form-data.
When was REDHAT-BUG-2454488 published?
REDHAT-BUG-2454488 was published on April 2, 2026.