s2Member <= 261106 - Unauthenticated Stored Cross-Site Scripting via PayPal Return Tracking Codes
- ID
- WPSEC-2026-2903
- Plugin
- s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions (s2member)
- Affected
- all versions before 261110
- Remediation
- Update to 261110 or later.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- Weakness
- CWE-79
- Usage
- Plugin Low · Affected versions Low among sites WPSec scans, 2026-11-12
- Attack surface
- s2Member on WPSec AttackSurface
- Fix released
- Published
Description
The s2member plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the PayPal return-page tracking codes feature (Signup, Modification, Capability and Specific Post/Page tracking codes) in all versions up to, and including, 261106, due to insufficient sanitization of payer-supplied PayPal values (such as first name, last name, payer email, item name and custom values) inserted into the tracking code template, and the stored result being output through do_shortcode() without escaping. This makes it possible for unauthenticated attackers who complete a PayPal payment to inject arbitrary web scripts or shortcodes that run in the browser that processes the payment's return link, for example a user tricked into opening that link. Exploitation requires tracking codes with the affected placeholders to be configured.
References
- https://wpsec.com/vuln/WPSEC-2026-2903/
- https://plugins.svn.wordpress.org/s2member/tags/261110/
- https://wordpress.org/plugins/s2member/
Published by WPSec. Provided as is, without warranty. Corrections: contact us.
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