# CVE-2025-44136: Tileserver - XSS

> Live exploitation tracking for CVE-2025-44136 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2025-44136

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 9.8
- **Public exploit available:** Yes
- **Affected products:** MapTiler Tileserver
- **Weaknesses:** CWE-79 (Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'))
- **Tags:** file_sharing

## Description

MapTiler Tileserver-php v2.0 is vulnerable to Cross Site Scripting (XSS). The GET parameter "layer" is reflected in an error message without html encoding. This leads to XSS and allows an unauthenticated attacker to execute arbitrary HTML or JavaScript code on a victim's browser.

## CrowdSec analysis

[CVE-2025-44136](https://euvd.enisa.europa.eu/vulnerability/CVE-2025-44136) is a critical cross-site scripting (XSS) vulnerability in MapTiler Tileserver-php v2.0, where the "layer" GET parameter is improperly handled and reflected in error messages without proper HTML encoding. This flaw allows unauthenticated attackers to inject and execute arbitrary HTML or JavaScript code in a victim's browser, potentially leading to session hijacking, credential theft, or other malicious actions.

CrowdSec has been tracking this vulnerability and its exploits since 26th of November 2025.

CrowdSec network observations suggest that most exploitation of CVE-2025-44136 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental.
Telemetry from the CrowdSec network also shows that exploitation activity for CVE-2025-44136 remains steady week-over-week. Attack volumes are consistent with long-term trends, indicating sustained interest from threat actors. CVE-2025-44136 continues to be an active part of the threat landscape and will likely remain this way for the forseeable future.

Attackers exploit this vulnerability by sending requests to URLs like `/tileserver.php/wmts/x/1/1/asd` with a crafted `layer` parameter containing malicious JavaScript, resulting in reflected XSS in error messages.

## Timeline

- 2025-07-29: CVE Published. CVE-2025-44136 is published to NVD.
- 2025-11-26: Rule Released. CrowdSec releases a rule to detect CVE-2025-44136 exploitation attempts against the CrowdSec Network.
- 2025-11-27: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2025-44136 for the first time.

## References

- https://github.com/mheranco/CVE-2025-44136
- https://github.com/maptiler/tileserver-php/issues/167
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-44136.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2025-44136) follows observed exploitation activity for CVE-2025-44136. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.