CVE-2026-92247: SynaptikCMS Unrestricted Upload RCE Vulnerability

CVE-2026-92247 Overview

CVE-2026-92247 is an unrestricted file upload vulnerability in Synaptik CMS versions up to 1.3.4.4. The flaw resides in the rename function of admin/file-manager.php, part of the Admin File Manager component. An authenticated attacker with high privileges can manipulate the rename operation to upload files without restriction. The issue is remotely exploitable across the network and has been publicly disclosed. Version 1.3.5 remediates the vulnerability, and the vendor recommends upgrading the affected component. The weakness is classified under CWE-284: Improper Access Control.

Critical Impact

An authenticated administrator can abuse the file manager rename functionality to place arbitrary files on the server, enabling persistence or further tampering within the CMS environment.

Affected Products

• Synaptik CMS versions up to and including 1.3.4.4
• Component: Admin File Manager (admin/file-manager.php)
• Fixed in: Synaptik CMS 1.3.5

Discovery Timeline

• 2026-09-16 - CVE-2026-92247 published to NVD
• 2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-92247

Vulnerability Analysis

The vulnerability exists in the rename function inside admin/file-manager.php. The function accepts user-controlled input for file naming operations but does not adequately restrict the resulting file characteristics. As a result, an attacker can influence the rename operation to produce files whose extensions or content types fall outside the intended allow list. This condition maps to CWE-284 because access controls governing which files may be created, renamed, or overwritten are not enforced correctly. The behavior falls under the Unrestricted File Upload class of web application flaws. Successful exploitation requires authenticated access with elevated privileges, which reduces the practical attack surface. The current EPSS probability is 0.294% at the 22.081 percentile, indicating limited observed exploitation activity to date.

Root Cause

The root cause is improper access control over rename operations exposed by the Admin File Manager. The rename handler trusts caller-supplied parameters when validating destination filenames, allowing an attacker to bypass extension or path constraints that would otherwise block executable or interpreter-parsed files.

Attack Vector

Exploitation is performed over the network against the CMS administrative interface. An attacker authenticated to an administrative account issues a crafted request to admin/file-manager.php invoking the rename operation. By manipulating the target file name, the attacker converts an existing file into an unrestricted upload artifact that the web server may serve or execute. No user interaction is required beyond the attacker's authenticated session.

No verified exploitation code is available. See the GitHub Security Research repository and the VulDB CVE-2026-92247 entry for additional technical detail.

Detection Methods for CVE-2026-92247

Indicators of Compromise

• Unexpected files with executable or script extensions (.php, .phtml, .phar) appearing in directories managed by the CMS file manager.
• HTTP requests to admin/file-manager.php invoking the rename action with unusual destination filenames or extension changes.
• New or modified files in web-accessible directories that do not correspond to legitimate administrator activity.

Detection Strategies

• Review web server access logs for POST requests targeting admin/file-manager.php with rename parameters, correlating against known administrator sessions.
• Enable file integrity monitoring on the CMS document root and upload directories to flag new or renamed executable files.
• Alert on administrator authentication events followed by file manager operations from atypical source IP addresses or user agents.

Monitoring Recommendations

• Ingest CMS application logs and web server logs into a centralized analytics platform to correlate administrative actions with filesystem changes.
• Track anomalous administrator behavior patterns, including bulk rename operations or rename requests targeting files with non-standard extensions.
• Monitor outbound connections from the web server process for signs of post-exploitation activity such as reverse shells or data staging.

How to Mitigate CVE-2026-92247

Immediate Actions Required

• Upgrade Synaptik CMS to version 1.3.5 or later as provided in the GitHub Release v1.3.5.
• Audit all administrator accounts and rotate credentials for any account that could have been misused prior to patching.
• Inspect the CMS upload and file manager directories for unexpected files, and remove any artifacts that cannot be attributed to legitimate activity.

Patch Information

The vendor addresses the issue in Synaptik CMS 1.3.5. Refer to the GitHub Release v1.3.5 for the fixed build and the VulDB CVE-2026-92247 entry for additional context.

Workarounds

• Restrict network access to the admin/ interface using IP allow lists or a VPN until the patch is applied.
• Enforce web server-level restrictions that prevent execution of script files in directories writable by the CMS file manager.
• Disable or limit access to the Admin File Manager component for administrators who do not require it.

# Example nginx configuration to block script execution in upload directories
location ~* ^/uploads/.*\.(php|phtml|phar)$ {
    deny all;
    return 403;
}