CVE-2026-3641 json
Appmax <= 1.0.3 - Missing Authorization to Order Status Manipulation and Arbitrary Order Creation via Webhook Endpoint
published 7mo ago modified 4mo ago also EUVD-2026-14187
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 25%
- public exploits
- 0
- none known
Summary
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.
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7mo ago
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Affected products
- appmaxplataforma Appmax
Classification
- Weakness
-
- CWE-20 Improper Input Validation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/6bf61bb7-f977-4afe-bb81-e6de12e00b03?source=cve
- plugins.trac.wordpress.org /browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L18
- plugins.trac.wordpress.org /browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L18
- plugins.trac.wordpress.org /browser/appmax/trunk/includes/core/class-appmax-payments-webhook.php#L28
- plugins.trac.wordpress.org /browser/appmax/tags/1.0.3/includes/core/class-appmax-payments-webhook.php#L28
- plugins.trac.wordpress.org /browser/appmax/trunk/includes/webhooks/class-appmax-payments-webhook-events.php#L103
- plugins.trac.wordpress.org /browser/appmax/tags/1.0.3/includes/webhooks/class-appmax-payments-webhook-events.php#L103
- plugins.trac.wordpress.org /browser/appmax/trunk/includes/webhooks/types/class-appmax-payments-order-paid.php#L56
- plugins.trac.wordpress.org /browser/appmax/tags/1.0.3/includes/webhooks/types/class-appmax-payments-order-paid.php#L56
Sources
- CVE List CVE-2026-3641
- NVD CVE-2026-3641
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