CVE-2026-55795: Craft Commerce Remote Code Execution Vulnerability

MODERATE
Advisory Identifier: GHSA-h5gm-x9wr-vhcm
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CWE-307
Published
Advisory Summary

CVE-2026-55795 is a MODERATE remote code execution vulnerability (CWE-307: Improper Restriction of Excessive Authentication Attempts) affecting Craft Commerce libraries in the Packagist ecosystem. The issue involves coupon code brute-force via rate limit bypass. Remediation is available by upgrading affected packages to version 5.6.5, 4.11.2.

CVE-2026-55795 at a Glance

CVE Identifier CVE-2026-55795
GHSA Identifier GHSA-h5gm-x9wr-vhcm
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-307: Improper Restriction of Excessive Authentication Attempts
Affected Product Craft Commerce
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-55795

To remediate this vulnerability, upgrade all affected Craft Commerce dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

craftcms/commerce fixed: 5.6.5 
Upgrade craftcms/commerce to 5.6.5
craftcms/commerce fixed: 4.11.2 
Upgrade craftcms/commerce to 4.11.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for craftcms/commerce

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-55795, inspect your project dependencies for Craft Commerce:

inspect dependencies for craftcms/commerce

Analyze the terminal output to locate any version of Craft Commerce in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.6.5), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-307: Improper Restriction of Excessive Authentication Attempts, where the product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame. In Craft Commerce, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The CartController defines a RateLimiter behavior that is only activated when the 'number' POST/GET parameter is explicitly provided. ### Details When an attacker submits coupon codes against the session-based cart (without passing a 'number' parameter), no rate limiting is applied. This allows unlimited attempts to guess coupon codes. **Vulnerable Code** <img width="864" height="90" alt="resim" src="https://github.com/user-attachments/assets/a5197f10-f1fd-4331-93f9-9479d0ceebba" /> <img width="881" height="272" alt="resim" src="https://github.com/user-attachments/assets/d9db963f-5d1f-4b00-a4b4-5f2dfe2b71dd" /> <img width="861" height="271" alt="resim" src="https://github.com/user-attachments/assets/f7842493-3bc0-4e99-956c-7266bab15703" /> ### PoC Complete instructions, including specific configuration details, to reproduce the vulnerability. <img width="909" height="171" alt="resim" src="https://github.com/user-attachments/assets/cfc8c994-5e0c-48de-b728-464029beba0e" /> ### Impact An attacker can enumerate all coupon codes through automated requests. **Remediation** Apply rate limiting unconditionally on actionUpdateCart regardless of whether 'number' is present.

CVE-2026-55795 Affected Craft Commerce Versions

2 component(s)
Fixed Versions:
5.6.54.11.2
Product / Package Ecosystem Affected Versions Fixed Version
craftcms/commerce
 Packagist
≥ 5.0.0
< 5.6.5
5.6.5
craftcms/commerce
 Packagist
≥ 4.0.0
< 4.11.2
4.11.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/craftcms/commerce/security/advisories/GHSA-h5gm-x9wr-vhcm
Security Fix Commit FIX COMMIT
https://github.com/craftcms/commerce/commit/df22c4f9c4ea7fb7857d833f755e49ea6f9f5bb5
Craft Commerce Source Repository REPOSITORY
https://github.com/craftcms/commerce

Frequently Asked Questions

What is CVE-2026-55795?
CVE-2026-55795 is a security vulnerability in Craft Commerce involving Coupon Code Brute-Force via Rate Limit Bypass under CWE-307: Improper Restriction of Excessive Authentication Attempts.
Which Craft Commerce versions are affected?
Affected versions include releases prior to 5.6.5, 4.11.2 across affected packages: craftcms/commerce.
What version fixes CVE-2026-55795?
Upgrading to 5.6.5, 4.11.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is craftcms/commerce affected?
Yes, craftcms/commerce is affected in releases prior to 5.6.5, 4.11.2. Upgrade your dependency to 5.6.5, 4.11.2 or later.
What CWE is associated with CVE-2026-55795?
CVE-2026-55795 is classified under CWE-307: Improper Restriction of Excessive Authentication Attempts (The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.).
How can I check Packagist dependencies for CVE-2026-55795?
Run the dependency tree command: 'inspect dependencies for craftcms/commerce'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h5gm-x9wr-vhcm",
  "modified" : "2026-06-19T21:15:26Z",
  "published" : "2026-06-19T21:15:26Z",
  "aliases" : [ "CVE-2026-55795" ],
  "summary" : "Craft Commerce: Coupon Code Brute-Force via Rate Limit Bypass",
  "details" : "### Summary\n\nThe CartController defines a RateLimiter behavior that is only activated when the 'number' POST/GET parameter is explicitly provided.\n\n### Details\n\nWhen an attacker submits coupon codes against the session-based cart (without passing a 'number' parameter), no rate limiting is applied. This allows unlimited attempts to guess coupon codes.\n\n**Vulnerable Code**\n<img width=\"864\" height=\"90\" alt=\"resim\" src=\"https://github.com/user-attachments/assets/a5197f10-f1fd-4331-93f9-9479d0ceebba\" />\n\n<img width=\"881\" height=\"272\" alt=\"resim\" src=\"https://github.com/user-attachments/assets/d9db963f-5d1f-4b00-a4b4-5f2dfe2b71dd\" />\n\n<img width=\"861\" height=\"271\" alt=\"resim\" src=\"https://github.com/user-attachments/assets/f7842493-3bc0-4e99-956c-7266bab15703\" />\n\n### PoC\nComplete instructions, including specific configuration details, to reproduce the vulnerability.\n\n<img width=\"909\" height=\"171\" alt=\"resim\" src=\"https://github.com/user-attachments/assets/cfc8c994-5e0c-48de-b728-464029beba0e\" />\n\n### Impact\nAn attacker can enumerate all coupon codes through automated requests.\n\n**Remediation**\nApply rate limiting unconditionally on actionUpdateCart regardless of whether 'number' is present.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/commerce"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0"
      }, {
        "fixed" : "5.6.5"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.6.4"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/commerce"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.11.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.11.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/commerce/security/advisories/GHSA-h5gm-x9wr-vhcm"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/commerce/commit/df22c4f9c4ea7fb7857d833f755e49ea6f9f5bb5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/commerce"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-307" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T21:15:26Z",
    "nvd_published_at" : null
  }
}