CVE-2025-15437: LigeroSmart XSS Vulnerability

CVE-2025-15437 Overview

A Cross-Site Scripting (XSS) vulnerability was discovered in LigeroSmart versions up to 6.1.24. The vulnerability exists in the Environment Variable Handler component, specifically in how the REQUEST_URI environment variable is processed. An attacker can exploit this flaw by manipulating the REQUEST_URI argument to inject malicious scripts, which are then reflected in HTTP redirect responses without proper sanitization.

Critical Impact
Remote attackers can inject malicious scripts through the REQUEST_URI parameter, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of authenticated users.

Affected Products

LigeroSmart versions up to 6.1.24
Kernel/System/Web/InterfaceAgent.pm
Kernel/System/Web/InterfaceCustomer.pm

Discovery Timeline

2026-01-02 - CVE-2025-15437 published to NVD
2026-01-02 - Last updated in NVD database

Technical Details for CVE-2025-15437

Vulnerability Analysis

This vulnerability is classified as Cross-Site Scripting (CWE-79) and affects the web interface components of LigeroSmart. The flaw originates from improper sanitization of the REQUEST_URI environment variable before it is used in HTTP redirect responses. When the application performs HTTPS redirects, it directly incorporates the unsanitized REQUEST_URI value into the Location header, allowing attackers to inject HTML and JavaScript code.

The vulnerability can be exploited remotely by an authenticated user with low privileges, though user interaction is required for successful exploitation. The attack targets the integrity of the application by enabling script injection, though confidentiality and availability are not directly impacted.

Root Cause

The root cause of this vulnerability is the lack of input validation on the REQUEST_URI environment variable in both InterfaceAgent.pm and InterfaceCustomer.pm files. The application directly used $ENV{REQUEST_URI} in constructing HTTP redirect headers without removing potentially dangerous characters such as <, >, ", ', and backticks. This allowed attackers to craft malicious URIs containing JavaScript payloads that would be reflected in the response.

Attack Vector

The attack is network-based and requires the attacker to craft a malicious URL containing XSS payload characters in the request path. When a victim clicks on this crafted link and the application performs an HTTPS redirect, the malicious payload is reflected in the redirect response. This can be leveraged for:

Session cookie theft via JavaScript
Phishing attacks by injecting fake login forms
Keystroke logging and credential harvesting
Redirecting users to malicious external sites

The security patch addresses this by implementing comprehensive input sanitization:

perl

# Sanitize REQUEST_URI to prevent XSS attacks
my $RequestURI = $ENV{REQUEST_URI} || '/';
# Remove HTML/script injection characters
$RequestURI =~ s/[<>"'`]//g;
# Remove control characters
$RequestURI =~ s/[\\x00-\\x1F\\x7F]//g;
# If URI becomes empty or invalid after sanitization, use default
$RequestURI = '/' if $RequestURI !~ m{^/};

# Redirect with 301 code. Add two new lines at the end, so HTTP headers are validated correctly.
print "Status: 301 Moved Permanently\nLocation: https://$Host$RequestURI\n\n";

Source: GitHub Commit Details

Detection Methods for CVE-2025-15437

Indicators of Compromise

HTTP requests containing XSS payloads in the URI path (characters like <script>, onerror=, javascript:)
Unusual redirect responses with embedded HTML or JavaScript in Location headers
Access logs showing requests with encoded special characters (%3C, %3E, %22, %27) in URIs
Client-side errors or unexpected script execution on LigeroSmart pages

Detection Strategies

Deploy Web Application Firewall (WAF) rules to detect and block requests containing XSS patterns in URIs
Monitor HTTP response headers for anomalous content in Location redirects
Implement intrusion detection signatures for common XSS payload patterns targeting REQUEST_URI
Review web server access logs for requests containing HTML/JavaScript injection attempts

Monitoring Recommendations

Enable detailed logging of all HTTP redirect responses from LigeroSmart
Configure alerting for requests containing special characters commonly used in XSS attacks
Monitor for client-side JavaScript errors that may indicate successful XSS exploitation
Track user session anomalies that could result from session hijacking attempts

How to Mitigate CVE-2025-15437

Immediate Actions Required

Upgrade LigeroSmart to version 6.1.26 or 6.3 immediately
Apply the security patch identified by commit hash 264ac5b2be5b3c673ebd8cb862e673f5d300d9a7
Review web server logs for any evidence of exploitation attempts
Implement Content Security Policy (CSP) headers as an additional defense layer

Patch Information

The vulnerability has been addressed in LigeroSmart versions 6.1.26 and 6.3. The patch implements proper sanitization of the REQUEST_URI environment variable by removing dangerous characters before use in HTTP redirects. The fix is available via the GitHub Release v6.1.26. For detailed technical information about the patch, refer to GitHub Issue #278.

Workarounds

Implement a reverse proxy with XSS filtering capabilities in front of LigeroSmart
Configure web server rules to sanitize REQUEST_URI before passing to the application
Deploy a WAF with XSS protection rules specifically targeting URI-based injection
Disable HTTPS redirect functionality temporarily if not operationally required

bash

# Example Apache mod_security rule to block XSS in REQUEST_URI
SecRule REQUEST_URI "@rx [<>\"'`]" \
    "id:100001,phase:1,deny,status:403,log,msg:'Potential XSS in REQUEST_URI'"