CVE-2025-14063: SEO Links Interlinking XSS Vulnerability

CVE-2025-14063 Overview

The SEO Links Interlinking plugin for WordPress contains a Reflected Cross-Site Scripting (XSS) vulnerability in the google_error parameter affecting all versions up to and including 1.7.5. The vulnerability exists due to insufficient input sanitization and output escaping, allowing unauthenticated attackers to inject arbitrary web scripts into pages that execute when a user is tricked into clicking a malicious link.

Critical Impact

Unauthenticated attackers can execute arbitrary JavaScript in the context of a victim's browser session, potentially leading to session hijacking, credential theft, or malicious actions performed on behalf of authenticated WordPress administrators.

Affected Products

• SEO Links Interlinking plugin for WordPress versions up to and including 1.7.5
• WordPress installations with the vulnerable plugin installed and active
• Sites where administrative users may interact with attacker-crafted URLs

Discovery Timeline

• 2026-01-28 - CVE-2025-14063 published to NVD
• 2026-01-29 - Last updated in NVD database

Technical Details for CVE-2025-14063

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The flaw resides in the scdata.php file of the SEO Links Interlinking plugin, specifically around lines 504 and 512 where the google_error parameter is processed.

The plugin fails to properly sanitize user-supplied input from the google_error parameter before reflecting it back to the user in the rendered HTML output. This oversight allows attackers to craft malicious URLs containing JavaScript payloads that execute in the context of the victim's browser when clicked.

Since the vulnerability is reflected rather than stored, exploitation requires social engineering to convince a user (typically a WordPress administrator) to click a specially crafted link. However, the lack of authentication requirements significantly lowers the barrier to exploitation.

Root Cause

The root cause is insufficient input sanitization and output escaping in the plugin's error handling mechanism. When the google_error parameter is passed to the application, its value is directly included in the page output without proper encoding or filtering. PHP and WordPress provide numerous sanitization functions such as esc_html(), esc_attr(), and wp_kses() that should be applied to user input before output, but these protections were not implemented for this parameter.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker constructs a malicious URL containing JavaScript code in the google_error parameter and distributes it through phishing emails, social media, or other channels. When an authenticated WordPress user clicks the link, the malicious script executes in their browser session with the same privileges as the user, enabling actions such as:

• Stealing session cookies or authentication tokens
• Performing administrative actions on behalf of the victim
• Defacing the WordPress site
• Redirecting users to malicious websites
• Injecting keyloggers or other malware

The vulnerability mechanism involves the reflection of unsanitized google_error parameter values in the plugin's admin interface. When processing this parameter in scdata.php, the plugin fails to apply WordPress escaping functions before rendering the output. An attacker can craft a URL such as https://target-site.com/wp-admin/admin.php?page=seo-links-interlinking&google_error=<script>malicious_code()</script> which, when visited by an administrator, would execute the injected script. For detailed code analysis, see the WordPress Plugin Code Review.

Detection Methods for CVE-2025-14063

Indicators of Compromise

• Unusual URL requests to WordPress admin pages containing google_error parameter with script tags or encoded JavaScript
• Web server logs showing access patterns with URL-encoded payloads targeting the SEO Links Interlinking plugin
• Unexpected administrative actions or settings changes following user access to suspicious URLs
• Reports from users of unexpected browser behavior when accessing WordPress admin areas

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block XSS patterns in the google_error parameter
• Monitor web server access logs for requests containing suspicious URL parameters with script tags, event handlers, or encoded JavaScript
• Deploy browser-based XSS detection using Content Security Policy (CSP) violation reporting
• Use WordPress security plugins to scan for vulnerable plugin versions and suspicious activity

Monitoring Recommendations

• Enable detailed logging for WordPress admin area access and monitor for unusual parameter patterns
• Configure alerts for HTTP requests containing common XSS payloads such as <script>, javascript:, or encoded variants
• Review referrer headers for links originating from suspicious or unknown sources
• Implement real-time monitoring for changes to WordPress user sessions or administrative settings

How to Mitigate CVE-2025-14063

Immediate Actions Required

• Update the SEO Links Interlinking plugin to a patched version when available from the WordPress plugin repository
• Temporarily deactivate the SEO Links Interlinking plugin if updates are not yet available and the functionality is not critical
• Implement WAF rules to block requests containing potentially malicious content in the google_error parameter
• Educate WordPress administrators about the risks of clicking unknown or suspicious links

Patch Information

Check the WordPress Plugin Details Page for the latest version information and security updates. The Wordfence Vulnerability Report provides additional details on the vulnerability status and remediation guidance.

Workarounds

• Implement Content Security Policy (CSP) headers to restrict script execution sources and mitigate XSS impact
• Use a WAF or security plugin to filter malicious input in URL parameters before they reach the vulnerable code
• Restrict access to WordPress admin areas to trusted IP addresses where possible
• Consider using browser extensions that block reflected XSS attacks as an additional layer of protection

# Example Content Security Policy header configuration for Apache
# Add to .htaccess or virtual host configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none';"

# Example WAF rule to block XSS in google_error parameter (ModSecurity)
SecRule ARGS:google_error "@rx (?i)(<script|javascript:|on\w+\s*=)" \
    "id:100001,phase:2,deny,status:403,msg:'XSS attempt in google_error parameter'"