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CVE-2026-3641 Detail

Description

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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L18 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L28 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/webhooks/class-appmax-payments-webhook-events.php#L103 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/tags/1.0.3/includes/webhooks/types/class-appmax-payments-order-paid.php#L56 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L18 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L28 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/webhooks/class-appmax-payments-webhook-events.php#L103 Wordfence
https://plugins.trac.wordpress.org/browser/appmax/trunk/includes/webhooks/types/class-appmax-payments-order-paid.php#L56 Wordfence
https://www.wordfence.com/threat-intel/vulnerabilities/id/6bf61bb7-f977-4afe-bb81-e6de12e00b03?source=cve Wordfence

Weakness Enumeration

CWE-ID CWE Name Source
CWE-20 Improper Input Validation Wordfence  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-3641
NVD Published Date:
03/21/2026
NVD Last Modified:
03/21/2026
Source:
Wordfence