CVE-2026-24848: OpenEMR RCE Vulnerability

CVE-2026-24848 Overview

OpenEMR, a widely-used free and open source electronic health records (EHR) and medical practice management application, contains a critical arbitrary file write vulnerability in versions 7.0.4 and earlier. The disposeDocument() method in EtherFaxActions.php allows authenticated users to write arbitrary content to arbitrary locations on the server filesystem. This vulnerability can be exploited to achieve Remote Code Execution (RCE) by uploading malicious PHP web shells.

Critical Impact

Authenticated attackers can write malicious PHP files to the web root, enabling complete server compromise and potential access to sensitive patient health information stored in the EHR system.

Affected Products

• OpenEMR versions 7.0.4 and earlier
• All OpenEMR installations using the EtherFax integration module
• Healthcare organizations running vulnerable OpenEMR deployments

Discovery Timeline

• 2026-03-03 - CVE-2026-24848 published to NVD
• 2026-03-04 - Last updated in NVD database

Technical Details for CVE-2026-24848

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Path Traversal), where the disposeDocument() method in the EtherFaxActions.php file fails to properly validate or sanitize user-supplied file path inputs. The function accepts user-controlled parameters that determine where file content is written on the server's filesystem.

Because the application runs with web server privileges, an authenticated attacker can leverage this flaw to write files to any location writable by the web server process. The most critical exploitation scenario involves writing a PHP web shell to a publicly accessible directory, effectively granting the attacker arbitrary code execution capabilities on the server.

In healthcare environments running OpenEMR, successful exploitation could lead to unauthorized access to Protected Health Information (PHI), violating HIPAA compliance requirements and potentially exposing thousands of patient records.

Root Cause

The root cause lies in insufficient input validation within the disposeDocument() method. The function accepts file path parameters without adequately sanitizing path traversal sequences (such as ../) or validating that the destination path falls within an expected directory. This allows attackers to escape the intended directory structure and write files to arbitrary locations on the filesystem.

Attack Vector

The attack requires network access and authentication to the OpenEMR application. Once authenticated, even with low-privilege access, an attacker can craft a malicious request to the disposeDocument() method, specifying a path outside the intended document storage location. By including path traversal sequences and targeting a web-accessible directory, the attacker can upload a PHP web shell that provides persistent remote code execution capabilities.

The vulnerability is particularly dangerous in multi-user OpenEMR environments where various staff members have authenticated access, as any compromised or malicious user account can be leveraged for exploitation.

Detection Methods for CVE-2026-24848

Indicators of Compromise

• Unexpected PHP files appearing in web-accessible directories outside normal upload locations
• Web server logs showing unusual requests to EtherFaxActions.php with path traversal sequences (../)
• New or modified files in the web root directory with recent timestamps
• Web shell signatures or suspicious PHP files containing functions like eval(), system(), exec(), or passthru()

Detection Strategies

• Monitor file integrity of web-accessible directories for unauthorized file creation or modification
• Implement web application firewall (WAF) rules to detect path traversal patterns in requests
• Review web server access logs for requests to EtherFaxActions.php containing suspicious path parameters
• Deploy endpoint detection and response (EDR) solutions to identify web shell behavior patterns

Monitoring Recommendations

• Configure file integrity monitoring (FIM) on OpenEMR installation directories
• Set up alerting for PHP process spawning system commands (potential web shell activity)
• Monitor network traffic for unusual outbound connections from the OpenEMR server
• Implement SIEM rules to correlate authentication events with subsequent file write operations

How to Mitigate CVE-2026-24848

Immediate Actions Required

• Upgrade OpenEMR to a patched version as soon as one becomes available
• Restrict network access to the OpenEMR application to trusted IP ranges only
• Review and audit all user accounts with access to the system, removing unnecessary privileges
• Implement additional access controls on sensitive directories to prevent unauthorized file writes
• Consider temporarily disabling the EtherFax integration module until patched

Patch Information

OpenEMR has published a security advisory for this vulnerability. System administrators should monitor the OpenEMR GitHub Security Advisory for patch availability and upgrade instructions. Organizations should prioritize applying the security update given the severity of the vulnerability and the sensitivity of healthcare data managed by OpenEMR.

Workarounds

• Implement web application firewall rules to block requests containing path traversal sequences to EtherFaxActions.php
• Apply filesystem permissions to restrict the web server's write access to only necessary directories
• Use PHP open_basedir configuration to limit the directories that PHP scripts can access
• Deploy intrusion detection/prevention systems (IDS/IPS) to detect and block exploitation attempts

# Example: Restrict PHP open_basedir in php.ini or Apache configuration
# Add to your PHP configuration to limit file system access
open_basedir = /var/www/openemr:/tmp

# Example: Apache configuration to block path traversal attempts
<LocationMatch ".*EtherFaxActions\.php.*">
    # Deny requests with path traversal patterns
    RewriteEngine On
    RewriteCond %{QUERY_STRING} \.\./ [NC]
    RewriteRule .* - [F,L]
</LocationMatch>