CVE-2026-3641 json
Appmax <= 1.0.3 - Missing Authorization to Order Status Manipulation and Arbitrary Order Creation via Webhook Endpoint
published 2026-03-21 7 mo ago modified 2026-06-17 4 mo 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 24%
- 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.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
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
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.