Craft Commerce is an ecommerce platform for Craft CMS. From 4.0.0 until 4.11.2 and 5.6.5, CartController in src/controllers/CartController.php activates its RateLimiter only when the number POST or GET parameter is supplied. An unauthenticated attacker can submit couponCode values to actionUpdateCart for the session-based cart while omitting number, preventing creation of the IP rate-limit identity and allowing unlimited automated coupon-code guessing and enumeration. This issue is fixed in versions 4.11.2 and 5.6.5.
https://github.com/craftcms/commerce/security/advisories/GHSA-h5gm-x9wr-vhcm
https://github.com/craftcms/commerce/releases/tag/5.6.5
https://github.com/craftcms/commerce/releases/tag/4.11.2
https://github.com/craftcms/commerce/commit/df22c4f9c4ea7fb7857d833f755e49ea6f9f5bb5
https://github.com/craftcms/commerce/commit/a7d365cc33dc4c60c543defb3458bcdb5749bc13
Published: 2026-09-14
Updated: 2026-09-14
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00295