GHSA-CRGH-3RC5-VQ96

Vulnerability from github – Published: 2026-03-21 06:30 – Updated: 2026-03-21 06:30
VLAI
Details

The Appmax plugin for WordPress is vulnerable to Improper Input Validation in all versions up to, and including, 1.0.3. This is due to the plugin registering a public REST API webhook endpoint at /webhook-system without implementing webhook signature validation, secret verification, or any mechanism to authenticate that incoming webhook requests genuinely originate from the legitimate Appmax payment service. The plugin directly processes untrusted attacker-controlled input from the 'event' and 'data' parameters without verifying the webhook's authenticity. This makes it possible for unauthenticated attackers to craft malicious webhook payloads that can modify the status of existing WooCommerce orders (e.g., changing them to processing, refunded, cancelled, or pending), create entirely new WooCommerce orders with arbitrary data, create new WooCommerce products with attacker-controlled names/descriptions/prices, and write arbitrary values to order post metadata by spoofing legitimate webhook events.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-3641"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-21T04:17:31Z",
    "severity": "MODERATE"
  },
  "details": "The Appmax plugin for WordPress is vulnerable to Improper Input Validation in all versions up to, and including, 1.0.3. This is due to the plugin registering a public REST API webhook endpoint at /webhook-system without implementing webhook signature validation, secret verification, or any mechanism to authenticate that incoming webhook requests genuinely originate from the legitimate Appmax payment service. The plugin directly processes untrusted attacker-controlled input from the \u0027event\u0027 and \u0027data\u0027 parameters without verifying the webhook\u0027s authenticity. This makes it possible for unauthenticated attackers to craft malicious webhook payloads that can modify the status of existing WooCommerce orders (e.g., changing them to processing, refunded, cancelled, or pending), create entirely new WooCommerce orders with arbitrary data, create new WooCommerce products with attacker-controlled names/descriptions/prices, and write arbitrary values to order post metadata by spoofing legitimate webhook events.",
  "id": "GHSA-crgh-3rc5-vq96",
  "modified": "2026-03-21T06:30:25Z",
  "published": "2026-03-21T06:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3641"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L18"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L28"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/webhooks/class-appmax-payments-webhook-events.php#L103"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/webhooks/types/class-appmax-payments-order-paid.php#L56"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L18"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L28"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/webhooks/class-appmax-payments-webhook-events.php#L103"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/webhooks/types/class-appmax-payments-order-paid.php#L56"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/6bf61bb7-f977-4afe-bb81-e6de12e00b03?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.