Cross-site Scripting (XSS) is a high-severity vulnerability that allows an attacker to inject malicious client-side scripts into a web application, which then executes these scripts on the victim's browser. If left unpatched, these vulnerabilities could lead to malicious actions, such as stealing user data, redirecting them to malicious sites, and performing unauthorized actions on their behalf.

Recently, a stored XSS vulnerability has been identified in the open-source framework pimcore (CVE-2023-2630). This vulnerability affects all versions prior to 10.5.21. In this post, we will explore the details of this vulnerability, the affected code snippets, and how to exploit it. We will also provide links to original references and resources to help you understand and remediate the vulnerability in your affected systems or applications.

The Vulnerability

CVE-2023-2630 allows an attacker to store malicious scripts in the pimcore framework, which can then be executed through a victim's browser when viewing specific content within the pimcore platform.

On 12 May 2023, a security researcher reported the vulnerability on the pimcore GitHub repository. Subsequently, the pimcore team patched this vulnerability in version 10.5.21, as mentioned in their GitHub release notes.

Affected Code Snippet

The vulnerability exists in the file Pimcore/Bundle/AdminBundle/Controller/Admin/AssetController.php, specifically the upload() function. An insufficient validation of the $filename parameter allows an attacker to bypass the filename validation and inject JavaScript code into the file.

Here's the affected code snippet

public function uploadAction(Request $request)
    $response = new JsonResponse();

    try {
        // ...

        $asset = Asset::create($parentFolder->getId(), [
            'filename' => $filename,
            'sourcePath' => $_FILES['Filedata']['tmp_name'],
            'userOwner' => $this->getUserId(),
            'userModification' => $this->getUserId()

        // ...
    } catch (\Exception $e) {
        // ...

Exploiting the Vulnerability

To exploit the vulnerability, an attacker can first modify the $filename variable by including XSS payloads within. At runtime, all files uploaded with malicious filenames will be stored in the application, leading the web application to serve malicious JavaScript code upon user interaction.

Here's a sample exploit payload


This payload combines an HTML script tag containing JavaScript code with the file extension of an image file. When a victim views a webpage containing an uploaded file with this payload, the browser will execute the injected JavaScript, causing an alert with the message 'XSS'.


To protect your systems or applications from this vulnerability, you should upgrade pimcore to version 10.5.21 or later. If upgrading is not immediately possible, consider implementing input validation and output encoding to mitigate risk. Future input validation should include validation checks for filenames and disallow specific characters or patterns that might allow XSS injection. Simultaneously, output encoding should render any injected scripts inert by encoding special characters as HTML entities.


Stored Cross-site Scripting (XSS) vulnerability (CVE-2023-2630) in pimcore can lead to serious security breaches if left unpatched. The pimcore team has addressed this issue in version 10.5.21. System administrators and developers using this framework should upgrade to a patched version or implement the suggested mitigation techniques to secure their applications.


1. GitHub Issue - XSS Vulnerability Report
2. pimcore - GitHub Release Notes
3. OWASP - XSS (Cross-site Scripting) Prevention Cheat Sheet


Published on: 05/10/2023 16:15:00 UTC
Last modified on: 05/17/2023 13:16:00 UTC