Compliance Impact

This vulnerability allows an authenticated user to upload and execute arbitrary PHP scripts on the server, leading to Remote Code Execution (RCE). Such an exploit can result in unauthorized access to sensitive data, modification of server files, and disruption of service.

Given the high impact on confidentiality, integrity, and availability, this vulnerability poses a significant risk to compliance with standards and regulations such as GDPR and HIPAA, which require protection of sensitive data and system integrity.

Failure to remediate this vulnerability could lead to data breaches or unauthorized data manipulation, potentially resulting in non-compliance with these regulations and associated legal and financial consequences.

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Executive Summary

CVE-2026-35164 is a high-severity vulnerability in BraveCMS versions prior to 2.0.6. It involves an unrestricted file upload flaw in the CKEditor upload functionality, specifically in the ckupload method of the CkEditorController.php file.

The vulnerability occurs because the method fails to properly validate the types of files being uploaded and relies entirely on user input. This allows an authenticated user with Author-level privileges or higher to upload executable PHP scripts disguised as images.

Once uploaded, these PHP scripts can be accessed and executed remotely, leading to Remote Code Execution (RCE) on the server. This means an attacker can run arbitrary code on the server, potentially taking full control.

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Impact Analysis

This vulnerability can have severe impacts including:

• Confidentiality: An attacker can access sensitive server data.
• Integrity: An attacker can modify server files arbitrarily.
• Availability: An attacker can disrupt or take down the server.
• Scope: The vulnerability affects the server component itself.
• Privileges Required: Only Author-level privileges are needed to exploit this.
• User Interaction: None required after authentication.
• Attack Complexity: Low, making exploitation relatively easy.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious file uploads to the CKEditor upload endpoint and checking for executable PHP files in the upload directory.

• Intercept POST requests to /dashboard/ckupload and inspect the uploaded files for unexpected PHP content or filenames such as shell.php.
• Search the upload directory (e.g., /images/articles/) for files with a .php extension that should not be present.
• Example command to find PHP files in the upload directory: `find /path/to/bravecms/public/images/articles/ -name '*.php'`
• Attempt to access suspicious PHP files with a command parameter to check for Remote Code Execution, e.g., `curl http://<server>/images/articles/<file>.php?cmd=id`.

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Mitigation Strategies

Immediate mitigation steps include applying strict file type validation on uploads, restricting script execution in the upload directory, and upgrading BraveCMS to version 2.0.6 or later.

• Implement Laravel request validation in the ckupload method to only allow image files with specific MIME types and size limits, for example: `$request->validate([ 'upload' => 'required|image|mimes:jpeg,jpg,png,gif|max:2048' ]);`
• Use secure methods like `$file->extension()` instead of relying on user-supplied file extensions.
• Configure the web server to deny execution of PHP scripts in the /images/articles directory to prevent execution of uploaded malicious files.
• Upgrade BraveCMS to version 2.0.6 or later where this vulnerability is fixed.

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