CVE-2026-26961
Rack's greedy multipart boundary parsing can cause parser differentials and WAF bypass.
描述
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.
如何修補 CVE-2026-26961
要修補 CVE-2026-26961,請將受影響套件升級到下列已修補版本。
- —未列出修補版本
- —升級至 2.2.23 或更新版本
CVE-2026-26961 正在被利用嗎?
低 — EPSS 為 0.3%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- from 0
- from 0, < 2.2.23
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |