Description
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser extracts the boundary parameter from multipart/form-data using a greedy regular expression. When a Content-Type header contains multiple boundary parameters, Rack selects the last one rather than the first. In deployments where an upstream proxy, WAF, or intermediary interprets the first boundary parameter, this mismatch can allow an attacker to smuggle multipart content past upstream inspection and have Rack parse a different body structure than the intermediary validated. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
INFO
Published Date :
2026-04-02T16:42:16.766Z
Last Modified :
2026-04-02T16:42:16.766Z
Source :
GitHub_M
AFFECTED PRODUCTS
The following products are affected by CVE-2026-26961 vulnerability.
No data.
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2026-26961.
