s2Member <= 260814 - Unauthenticated Remote Code Execution via 'first_name' Parameter in PayPal Proxy Return
| CVE | CVE-2026-19804 |
|---|---|
| CVSS | 8.8 (High) |
| Publicly Published | September 24, 2026 |
| Last Updated | September 25, 2026 |
| Researcher |
Supakiad S. (m3ez)
- E-CQURITY (Thailand)
|
Description
The s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 260814 via the 'first_name' parameter parameter. This is due to insufficient sanitization of the first_name parameter via esc_refs(), which strips only regex backreferences and not PHP tags, before substitution into the eval'd Signup Tracking Codes template, combined with disclosure of the site-global proxy verification key that allows PayPal postback verification to be bypassed. This makes it possible for unauthenticated attackers to execute code on the server. Successful exploitation requires that the site administrator has configured a Signup Tracking Codes template containing the %%first_name%% placeholder (a documented, GUI-supported feature) and that the attacker has obtained the site-global proxy verification key, which is exposed in plaintext in the JSON response of any PayPal Checkout AJAX request on the target site.
References
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
- plugins.trac.wordpress.org
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Vulnerability Details for s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions
| Software Type | Plugin |
|---|---|
| Software Slug | s2member (view on wordpress.org) |
| Patched? | Yes |
| Remediation | Update to version 260829, or a newer patched version |
| Affected Version |
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| Patched Version |
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Recent vulnerabilities in s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions
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