CVE-2026-19804
Received Received - Intake

Remote Code Execution in s2Member WordPress Plugin

Publication date: 2026-09-25

Last updated on: 2026-09-25

Assigner: Wordfence

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.

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Meta Information

Published
2026-09-25
Last Modified
2026-09-25
Generated
2026-09-25
AI Q&A
2026-09-25
EPSS Evaluated
N/A
NVD
CVE-2026-19804
EUVD
EUVD-2026-86577

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wp-s2member s2member to 260814 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

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Executive Summary

This vulnerability is a Remote Code Execution flaw in the s2Member WordPress plugin up to version 260814. It occurs due to insufficient sanitization of the 'first_name' parameter, which allows PHP tags to be injected. Attackers can exploit this by combining it with a disclosed site-global proxy verification key to bypass PayPal verification and execute arbitrary code on the server.

Detection Guidance

Check if the s2Member plugin is installed and verify its version. Look for Signup Tracking Codes templates containing the %%first_name%% placeholder in the WordPress admin panel. Inspect PayPal Checkout AJAX responses for exposed proxy verification keys in plaintext.

Impact Analysis

Unauthenticated attackers can execute malicious code on your server if they obtain the proxy verification key and the site uses a Signup Tracking Codes template with the %%first_name%% placeholder. This could lead to full system compromise, data theft, or further attacks on your WordPress site.

Compliance Impact

This vulnerability could lead to unauthorized access and data breaches, violating GDPR and HIPAA requirements for data protection and access control. A successful exploit may expose sensitive user data, resulting in legal penalties and compliance violations.

Mitigation Strategies

Update the s2Member plugin to the latest version immediately. Remove any Signup Tracking Codes templates containing the %%first_name%% placeholder. Rotate the site-global proxy verification key and restrict access to PayPal Checkout AJAX responses.

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