CVE-2025-23547: LH Login Page XSS Vulnerability

CVE-2025-23547 Overview

CVE-2025-23547 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the LH Login Page WordPress plugin developed by shawfactor. The vulnerability stems from improper neutralization of input during web page generation (CWE-79), allowing attackers to inject malicious scripts that execute in the context of a victim's browser session.

This vulnerability enables attackers to craft malicious URLs that, when clicked by an authenticated user, can execute arbitrary JavaScript code within the WordPress administration context. This can lead to session hijacking, credential theft, or further compromise of the WordPress installation.

Critical Impact

Attackers can exploit this Reflected XSS vulnerability to steal session cookies, perform actions on behalf of authenticated administrators, or redirect users to malicious websites. The vulnerability requires user interaction (clicking a malicious link) but can be exploited remotely without authentication.

Affected Products

• LH Login Page WordPress Plugin versions up to and including 2.14
• WordPress installations using vulnerable versions of the lh-login-page plugin

Discovery Timeline

• 2025-01-16 - CVE-2025-23547 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-23547

Vulnerability Analysis

The LH Login Page plugin fails to properly sanitize user-supplied input before reflecting it back in the web page output. This Reflected XSS vulnerability allows an attacker to inject malicious JavaScript code through URL parameters or form inputs that are rendered without adequate encoding or escaping.

When a user visits a specially crafted URL containing malicious JavaScript, the plugin processes the input and includes it directly in the HTML response. The victim's browser then executes the injected script with the same privileges as the legitimate page, effectively bypassing same-origin policy protections.

The attack requires user interaction—specifically, the victim must click a malicious link or be redirected to the vulnerable endpoint. However, once triggered, the attacker gains the ability to perform any action the victim could perform, including modifying WordPress settings, creating new administrator accounts, or installing malicious plugins.

Root Cause

The root cause of this vulnerability is the failure to implement proper input validation and output encoding in the LH Login Page plugin. Specifically, user-controlled data is reflected in the HTTP response without being sanitized through WordPress's built-in escaping functions such as esc_html(), esc_attr(), or wp_kses(). This lack of output encoding allows HTML and JavaScript content to be interpreted and executed by the browser rather than being displayed as plain text.

Attack Vector

The attack is network-based and requires no prior authentication to the WordPress site. An attacker can craft a malicious URL containing JavaScript payload and distribute it through phishing emails, social engineering, or by embedding the link in other web content. When an authenticated WordPress administrator clicks the link, the injected script executes within their browser session.

The attack can be leveraged to:

• Steal session cookies and authentication tokens
• Perform administrative actions on behalf of the victim
• Modify site content or inject persistent backdoors
• Redirect users to phishing pages or malware distribution sites

Technical details and proof-of-concept information can be found in the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2025-23547

Indicators of Compromise

• Unusual URL parameters containing JavaScript code, <script> tags, or encoded variations targeting the LH Login Page plugin endpoints
• Web server logs showing requests with suspicious payloads in query strings directed at login page customization features
• Unexpected administrative actions or new user accounts created without proper authorization
• Browser console errors or warnings related to Content Security Policy violations originating from login pages

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block XSS payloads in URL parameters targeting WordPress login endpoints
• Monitor web server access logs for requests containing common XSS patterns such as <script>, javascript:, onerror=, and similar injection vectors
• Deploy endpoint detection solutions that can identify malicious JavaScript execution in browser contexts
• Utilize WordPress security plugins that provide real-time scanning and anomaly detection for plugin vulnerabilities

Monitoring Recommendations

• Enable verbose logging for WordPress authentication and plugin activity to track potential exploitation attempts
• Configure alerting for unusual patterns in web traffic, particularly requests with encoded characters or excessive URL parameter lengths
• Implement Content Security Policy (CSP) headers to restrict script execution sources and provide violation reports
• Regularly audit WordPress user accounts and permissions to detect unauthorized changes resulting from XSS exploitation

How to Mitigate CVE-2025-23547

Immediate Actions Required

• Update the LH Login Page plugin to the latest available version that addresses this vulnerability
• If no patched version is available, consider temporarily deactivating the LH Login Page plugin until a security update is released
• Review WordPress user accounts and audit recent administrative actions for signs of compromise
• Implement Content Security Policy headers to provide defense-in-depth against XSS attacks

Patch Information

Administrators should check for updates to the LH Login Page plugin through the WordPress plugin repository or the developer's official channels. Monitor the Patchstack WordPress Vulnerability Report for updated remediation guidance and patch availability.

Until a patch is available, implementing the workarounds below can help reduce the risk of exploitation.

Workarounds

• Temporarily disable the LH Login Page plugin if custom login page functionality is not critical to operations
• Deploy a Web Application Firewall (WAF) with rules to block common XSS attack patterns targeting WordPress sites
• Implement strict Content Security Policy headers to prevent inline script execution and limit allowed script sources
• Educate administrators about the risks of clicking unknown links, especially while authenticated to the WordPress dashboard

# Add Content Security Policy header in .htaccess for Apache
# This provides defense-in-depth against XSS attacks
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline';"