CVE-2025-9878 Overview
CVE-2025-9878 is a stored Cross-Site Scripting (XSS) vulnerability [CWE-79] in the PPWP – Password Protect WordPress plugin. The flaw affects all versions up to and including 1.9.21. The plugin's ppwp shortcode fails to properly sanitize input and escape output on user-supplied attributes. Authenticated users with contributor-level access or higher can inject arbitrary JavaScript into pages. The injected scripts execute in the browser of any visitor who accesses the affected page.
Critical Impact
Authenticated contributors can inject persistent JavaScript that executes against site visitors and administrators, enabling session theft, forced redirects, and content manipulation.
Affected Products
- PPWP – Password Protect WordPress plugin versions up to and including 1.9.21
- WordPress sites using the ppwp shortcode
- Any WordPress installation permitting contributor-level or higher accounts on vulnerable plugin versions
Discovery Timeline
- 2026-08-25 - CVE-2025-9878 published to NVD
- 2026-08-26 - Last updated in NVD database
Technical Details for CVE-2025-9878
Vulnerability Analysis
The vulnerability resides in the plugin's shortcode handler, implemented in class-ppw-shortcode.php. When WordPress renders a page containing the ppwp shortcode, the handler processes user-supplied attributes without sufficient input sanitization or output escaping. An authenticated contributor can embed shortcode attributes that contain JavaScript payloads. Those payloads are stored in post content and served to every subsequent visitor of the page.
Because the shortcode output is rendered inline in the page HTML, the injected script executes in the security context of the site's origin. This yields a stored XSS primitive suitable for account takeover of higher-privileged users, cookie theft, and administrative action forgery when an administrator views the compromised content. The CVSS scope change reflects that the vulnerable component (the plugin shortcode) impacts the broader browser security context of visitors.
Root Cause
The root cause is missing input sanitization and missing output escaping on shortcode attributes handled by the PPWP shortcode service. WordPress provides helpers such as esc_attr(), esc_html(), and wp_kses() for exactly this purpose, but the vulnerable code path renders attribute values into HTML without applying them. See the WordPress Plugin Code Snippet and the fix in the WordPress Changeset Revision.
Attack Vector
An attacker requires an authenticated WordPress account at contributor level or higher. The attacker authors a post or page containing the ppwp shortcode with a crafted attribute value carrying JavaScript. Once the post is published or previewed by a higher-privileged user, the payload executes in that user's browser. Network access to the WordPress site is the only additional prerequisite; no user interaction beyond visiting the page is required.
Detection Methods for CVE-2025-9878
Indicators of Compromise
- Post or page content containing [ppwp ...] shortcodes with attribute values that include <script>, onerror=, onload=, or javascript: substrings.
- Unexpected outbound requests from administrator browsers to attacker-controlled domains shortly after viewing plugin-protected content.
- New administrator or editor accounts created without a corresponding audit trail from a known admin session.
Detection Strategies
- Query the wp_posts table for post_content values matching ppwp shortcodes with suspicious attribute contents.
- Deploy a web application firewall rule that flags shortcode attributes containing HTML event handlers or <script> tokens.
- Review WordPress audit logs for contributor-level users publishing or updating content that renders through the PPWP plugin.
Monitoring Recommendations
- Monitor authenticated content-creation activity from contributor and author roles for anomalous shortcode usage.
- Alert on Content Security Policy (CSP) violation reports originating from pages that embed the ppwp shortcode.
- Track plugin version inventory across WordPress sites and flag any host still running PPWP 1.9.21 or earlier.
How to Mitigate CVE-2025-9878
Immediate Actions Required
- Update the PPWP – Password Protect WordPress plugin to the version released after 1.9.21 that includes the sanitization fix.
- Audit existing posts and pages for malicious ppwp shortcode attributes and remove any injected payloads.
- Rotate session cookies and reset passwords for administrator accounts that may have viewed compromised content.
Patch Information
The vendor addressed the issue in commits published on WordPress.org plugin trac. Review the WordPress Changeset Revision and the follow-up WordPress Changeset Update. Additional analysis is available from Wordfence Vulnerability Overview and CleanTalk CVE Analysis.
Workarounds
- Restrict contributor-and-above role assignments to trusted users until the plugin is patched.
- Deploy a strict Content Security Policy that disallows inline scripts on pages rendering the ppwp shortcode.
- Temporarily disable the PPWP plugin on sites where an immediate update is not feasible.
# Configuration example: identify vulnerable PPWP installations via WP-CLI
wp plugin get password-protect-page --field=version
wp plugin update password-protect-page
# Search post content for suspicious ppwp shortcode attributes
wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content REGEXP '\\[ppwp[^]]*(<script|onerror=|onload=|javascript:)'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
