REDHAT-BUG-2454488: High severity Rack Rack vulnerability

Published Apr 2, 2026
·
Updated

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

1 affected component
Rack Rack<2.2.23, <3.1.21, <3.2.6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Rack to a version that resolves this vulnerability.

    Fixed in 2.2.23
  2. Upgrade

    Upgrade Rack to a version that resolves this vulnerability.

    Fixed in 3.1.21
  3. Upgrade

    Upgrade Rack to a version that resolves this vulnerability.

    Fixed in 3.2.6

Event History

Apr 2, 2026
Data Sourced
via Red Hat·06:01 PM
DescriptionSeverityAffected Software
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Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2454488?

The severity of REDHAT-BUG-2454488 is rated as high with a score of 7.

2

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.

3

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.

4

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.

5

When was REDHAT-BUG-2454488 published?

REDHAT-BUG-2454488 was published on April 2, 2026.

Contact

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