CVE-2025-15562: Server API Endpoint XSS Vulnerability

CVE-2025-15562 Overview

CVE-2025-15562 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the /report/internet/urls server API endpoint. The endpoint reflects received data into the HTML response without applying proper encoding or filtering, allowing attackers to execute arbitrary JavaScript code in the context of a victim's browser session.

Critical Impact

Attackers can craft malicious URLs that, when opened by victims, execute arbitrary JavaScript code in their browsers, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of authenticated users.

Affected Products

• Server application with /report/internet/urls endpoint (specific product details not disclosed)

Discovery Timeline

• 2026-02-19 - CVE-2025-15562 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2025-15562

Vulnerability Analysis

This vulnerability falls under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The /report/internet/urls API endpoint accepts user-controlled input and reflects it directly into the HTML response without proper sanitization or output encoding. This allows attackers to inject malicious script content that executes within the security context of the vulnerable application.

When a victim clicks on a specially crafted link containing malicious JavaScript payload, the server echoes this content back into the response page. The victim's browser interprets the injected script as legitimate application code and executes it with full access to the current session, cookies, and DOM elements.

Root Cause

The root cause is improper input validation and output encoding in the /report/internet/urls endpoint. The application fails to sanitize user-supplied data before including it in HTML responses, violating secure coding principles for web application development. Specifically, special HTML characters such as <, >, ", and ' are not properly escaped or encoded before being reflected in the response body.

Attack Vector

The attack requires social engineering to convince a victim to click on a malicious URL. The attacker crafts a URL containing JavaScript payload as a parameter value to the vulnerable endpoint. When the victim accesses this URL while authenticated to the application, the malicious script executes with the victim's privileges.

The exploitation chain typically involves:

1. Attacker identifies the vulnerable endpoint and parameter
2. Attacker constructs a malicious URL embedding JavaScript payload
3. Attacker distributes the link via phishing emails, social media, or compromised websites
4. Victim clicks the link while authenticated to the vulnerable application
5. Malicious JavaScript executes in the victim's browser session
6. Attacker achieves objectives such as session token theft, keylogging, or performing unauthorized actions

For detailed technical information about this vulnerability, refer to the SEC Consult Security Advisory.

Detection Methods for CVE-2025-15562

Indicators of Compromise

• Unusual URL patterns in web server logs containing encoded script tags or JavaScript payloads targeting /report/internet/urls
• HTTP requests to the vulnerable endpoint with suspicious parameter values containing <script>, javascript:, or event handler attributes
• Outbound connections from client browsers to unknown external domains following visits to the vulnerable endpoint

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing XSS payloads targeting the /report/internet/urls endpoint
• Deploy Content Security Policy (CSP) headers to restrict inline script execution and report policy violations
• Monitor web server access logs for requests with encoded HTML entities or JavaScript-related strings in URL parameters

Monitoring Recommendations

• Enable verbose logging on the web application to capture full request parameters for forensic analysis
• Configure browser-based XSS auditors and CSP violation reporting to identify exploitation attempts
• Set up alerts for anomalous patterns of requests to the vulnerable endpoint from single IP addresses

How to Mitigate CVE-2025-15562

Immediate Actions Required

• Apply vendor patches as soon as they become available
• Implement input validation to reject requests containing HTML or JavaScript syntax in URL parameters
• Deploy output encoding for all user-controlled data reflected in HTML responses
• Enable Content Security Policy headers with strict inline script restrictions

Patch Information

Patch information is not currently available in the CVE data. Monitor the SEC Consult Security Advisory for updates on remediation guidance and vendor response.

Workarounds

• Implement a Web Application Firewall rule to filter requests to /report/internet/urls containing common XSS patterns
• Add server-side output encoding for all reflected parameters using context-appropriate encoding functions
• Deploy strict Content Security Policy headers to prevent inline script execution even if XSS payload is reflected
• Consider temporarily restricting access to the vulnerable endpoint until a permanent fix is available

# Example CSP header configuration for Apache
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"