Can you explain this vulnerability to me?

The vulnerability CVE-2026-10807 is an unrestricted file upload flaw in the stumasy application, specifically in the change_profile_image.php script.

It occurs because the validation logic incorrectly uses an OR condition to check either the MIME type or the file extension against a whitelist. This allows attackers to bypass restrictions by forging the Content-Type header to a whitelisted MIME type (like image/png) while uploading a malicious PHP file with a .php extension.

The uploaded file is saved with its original extension in a web-accessible directory, enabling attackers to execute the uploaded PHP script remotely by accessing its URL, leading to Remote Code Execution (RCE).

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How can this vulnerability impact me? :

This vulnerability can have serious impacts as it allows an attacker to upload and execute arbitrary PHP code on the server remotely.

By exploiting this flaw, an attacker can gain Remote Code Execution (RCE) capabilities, potentially taking full control of the affected server, accessing sensitive data, modifying or deleting files, and disrupting services.

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How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring for suspicious file uploads to the change_profile_image.php endpoint, especially files with PHP extensions that are accepted despite MIME type checks.

One way to detect exploitation attempts is to look for HTTP POST requests to the change_profile_image.php script that include files with PHP extensions but have a forged Content-Type header such as image/png.

Commands to help detect this include inspecting web server access logs for such requests and searching for uploaded PHP files in web-accessible directories.

• Use grep or similar tools to find POST requests to change_profile_image.php with suspicious Content-Type headers, e.g.:
• grep -i 'POST /application/PHP/objects/profiles/change_profile_image.php' /var/log/apache2/access.log | grep -i 'Content-Type: image/png'
• Search for recently uploaded PHP files in the upload directory (replace with actual path):
• find /path/to/upload/directory -name '*.php' -mtime -7

Additionally, monitoring for execution of unexpected PHP scripts in web directories can help detect exploitation.

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What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation steps include disabling or restricting the file upload functionality in change_profile_image.php until a proper fix is applied.

Ensure that file validation logic uses an AND condition to verify both MIME type and file extension, preventing attackers from bypassing checks by forging headers.

Restrict upload directories so that uploaded files cannot be executed as scripts by the web server.

Implement server-side controls such as disabling PHP execution in upload directories via web server configuration (e.g., using .htaccess or equivalent).

Monitor and remove any suspicious uploaded files, especially those with PHP extensions.

Since the project has not yet responded with an official fix, consider applying custom patches or workarounds to improve validation and restrict execution.

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How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

The vulnerability allows unrestricted file upload leading to remote code execution, which can compromise the confidentiality, integrity, and availability of data on the affected system.

Such a security flaw could potentially lead to unauthorized access to personal or sensitive data, thereby impacting compliance with data protection regulations like GDPR and HIPAA that require safeguarding personal information.

However, the provided information does not explicitly state the impact on compliance with these standards.

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