CVE-2026-15047 Overview
CVE-2026-15047 is a stored cross-site scripting (XSS) vulnerability in the s2Member WordPress plugin versions prior to 260805. The plugin fails to escape several shortcode attributes before rendering them inside an inline script context. Users with contributor-level access can inject arbitrary JavaScript that executes when a visitor loads the affected post. The flaw is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation).
Critical Impact
Authenticated contributors can persist JavaScript payloads that execute in the browsers of site visitors and administrators, enabling session theft, privilege escalation through admin-targeted actions, and site defacement.
Affected Products
- s2Member WordPress plugin versions before 260805
- WordPress sites permitting contributor-level or higher registrations with s2Member installed
- Any post or page containing the vulnerable s2Member shortcodes
Discovery Timeline
- 2026-08-10 - CVE-2026-15047 published to NVD
- 2026-08-11 - Last updated in NVD database
Technical Details for CVE-2026-15047
Vulnerability Analysis
The s2Member plugin exposes shortcodes that accept user-controlled attributes and emit those attribute values directly into an inline <script> block on the rendered page. Because the plugin does not apply JavaScript-context escaping to those values, a contributor can close the string literal or the script tag structure and inject arbitrary JavaScript.
When an authenticated user with the contributor role saves a post containing a crafted shortcode, WordPress persists the payload in the database. Any subsequent page load that renders the post triggers execution of the attacker's script in the visitor's browser under the site's origin.
Exploitation requires authenticated access and user interaction to view the post, but the payload runs against every viewer, including administrators. This creates a path for cross-role privilege escalation via forged admin requests.
Root Cause
The root cause is missing output encoding on shortcode attribute values that flow into an inline script context. Safe rendering requires JavaScript-string escaping (for example, esc_js() in WordPress) rather than the HTML-context escaping applied elsewhere. The plugin uses insufficient or absent sanitization between the shortcode parser and the script emission point.
Attack Vector
An attacker with contributor-level credentials authors a post that embeds an s2Member shortcode with attribute values containing script-breaking characters and a JavaScript payload. After the post is published or previewed by a higher-privileged user, the injected script executes in that user's authenticated session. Attackers can chain the payload with WordPress REST API calls to create administrative accounts or modify site content. Refer to the WPScan Vulnerability Report for technical specifics.
Detection Methods for CVE-2026-15047
Indicators of Compromise
- Post or page content in wp_posts containing s2Member shortcodes with attribute values that include characters such as ", ';, </script>, or javascript: payloads
- Unexpected administrator or editor accounts created shortly after a contributor published or edited a post
- Outbound browser requests to unfamiliar domains originating from pages that render s2Member shortcodes
Detection Strategies
- Query the WordPress database for posts authored by contributor-role users that reference s2Member shortcodes and inspect attribute values for script syntax.
- Enable and monitor a Content Security Policy (CSP) in report-only mode to surface inline script violations tied to affected post URLs.
- Review web server access logs for anomalous POST activity to wp-admin/post.php and wp-admin/admin-ajax.php from contributor accounts.
Monitoring Recommendations
- Alert on new user registrations at editor or administrator level following post edits by contributor accounts.
- Track file integrity of WordPress core, plugins, and theme directories to catch webshells dropped via chained XSS-to-RCE actions.
- Log and review all shortcode attribute content submitted through the WordPress editor for contributor and author roles.
How to Mitigate CVE-2026-15047
Immediate Actions Required
- Update the s2Member plugin to version 260805 or later on all WordPress sites where it is installed.
- Audit contributor, author, and editor accounts and remove any that are inactive, unrecognized, or created without justification.
- Scan existing posts and pages for s2Member shortcode usage and inspect attribute values for injected JavaScript before restoring the site to production.
Patch Information
Upgrade the s2Member plugin to version 260805 or newer, which adds the missing JavaScript-context escaping on the affected shortcode attributes. Consult the WPScan Vulnerability Report for the corresponding fix reference.
Workarounds
- Restrict the contributor role by removing shortcode-authoring capabilities until the plugin is updated.
- Disable the s2Member plugin temporarily on sites that cannot immediately update.
- Enforce a strict Content Security Policy that disallows unsafe inline script execution to blunt exploitation until patched.
# Update s2Member via WP-CLI on the affected WordPress installation
wp plugin update s2member --version=260805
# Verify the installed version
wp plugin get s2member --field=version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
