CVE-2026-34827 Rack is a modular Ruby web server interface
Description
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Multipart::Parser#handle_mime_head parses quoted multipart parameters such as Content-Disposition: form-data; name="..." using repeated String#index searches combined with String#slice! prefix deletion. For escape-heavy quoted values, this causes super-linear processing. An unauthenticated attacker can send a crafted multipart/form-data request containing many parts with long backslash-escaped parameter values to trigger excessive CPU usage during multipart parsing. This results in a denial of service condition in Rack applications that accept multipart form data. This issue has been patched in versions 3.1.21 and 3.2.6.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Rack 3.2 | 3.2.0 → < 3.2.6 | 3.2.6 |
| Rack 3.0 | 3.0.0.beta1 → < 3.1.21 | 3.1.21 |
| Logging Subsystem for Red Hat OpenShift | Versions not published | |
| Red Hat 3scale API Management Platform 2 | Versions not published | |
| Red Hat Enterprise Linux 10 | Versions not published | |
| Red Hat Enterprise Linux 7 | Versions not published | |
| Red Hat Enterprise Linux 8 | Versions not published | |
| Red Hat Enterprise Linux 9 | Versions not published |
References
- github.com github.com
Timeline
- Published
- Last modified