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

> Attackers can bypass IP rate limits to brute-force coupon codes in Craft Commerce by omitting a specific parameter, enabling unlimited automated guessing.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-h5gm-x9wr-vhcm

## What is CVE-2026-55795?

CVE-2026-55795 is a medium-severity vulnerability in craftcms commerce, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2026-55795?

4 open source packages ship an affected version, including craftcms/commerce.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/commerce` | Packagist | From 4.0.0 | 4.11.2 |
| `craftcms/commerce` | Packagist | From 4.0.0 | 4.11.2 |
| `craftcms/commerce` | Packagist | From 5.0.0 | 5.6.5 |
| `craftcms/commerce` | Packagist | From 5.0.0 | 5.6.5 |

## How do I fix CVE-2026-55795?

Upgrade craftcms/commerce to a fixed version for your release line: 4.11.2 or 5.6.5.

## Is CVE-2026-55795 being exploited?

There is no known exploitation of CVE-2026-55795 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55795 and fix it if it is affected.

What it is: CVE-2026-55795 is a medium-severity vulnerability in craftcms commerce, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-55795 in the wild and no public exploit code.

Affected packages and fixed versions:
- craftcms/commerce (Packagist): affected from 4.0.0; fixed in 4.11.2
- craftcms/commerce (Packagist): affected from 4.0.0; fixed in 4.11.2
- craftcms/commerce (Packagist): affected from 5.0.0; fixed in 5.6.5
- craftcms/commerce (Packagist): affected from 5.0.0; fixed in 5.6.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55795/ (Markdown: https://insights.sbomify.com/CVE-2026-55795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55795
- OSV: https://osv.dev/vulnerability/CVE-2026-55795

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55795/
Summaries are generated and may contain mistakes; the official description above is the record.