Overview
Cybersecurity is a field that is constantly evolving with new vulnerabilities being discovered on a daily basis. One such vulnerability is the CVE-2025-44136, a high-risk Cross Site Scripting (XSS) vulnerability found in MapTiler Tileserver-php v2.0. This vulnerability can have severe implications including potential system compromise and data leakage. Considering the critical role that MapTiler Tileserver plays in various applications, it is important to understand the nature of this vulnerability and the steps that can be taken to mitigate it.
Vulnerability Summary
CVE ID: CVE-2025-44136
Severity: Critical with a CVSS score of 9.8
Attack Vector: Cross Site Scripting (XSS) via GET parameter
Privileges Required: None
User Interaction: Required
Impact: System compromise and potential data leakage
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Product | Affected Versions
MapTiler Tileserver-php | v2.0
How the Exploit Works
The vulnerability lies in the GET parameter “layer” of MapTiler Tileserver-php v2.0. This parameter is reflected in an error message without HTML encoding, making it vulnerable to Cross Site Scripting (XSS) attacks. Essentially, an unauthenticated attacker can manipulate the “layer” GET parameter to inject malicious JavaScript or HTML code. When a victim views the error message, the malicious code executes, potentially leading to system compromise or data leakage.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using an HTTP GET request:
GET /tileserver.php?layer=<img src=x onerror=alert('XSS')> HTTP/1.1
Host: vulnerable.example.comIn this example, the malicious payload is an HTML image tag with a JavaScript ‘onerror’ event handler. When the image fails to load, which it does because ‘x’ is not a valid source, the JavaScript code within the ‘onerror’ event handler (alert(‘XSS’)) is executed.
Mitigation Guidance
Users of MapTiler Tileserver-php v2.0 are advised to apply the vendor patch as soon as it becomes available. In the meantime, use of Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS) can serve as a temporary mitigation. These systems can be configured to detect and block attempts to exploit this vulnerability by looking for known malicious patterns in HTTP requests.