CVE-2025-70073: ChestnutCMS RCE Vulnerability

CVE-2025-70073 Overview

CVE-2025-70073 is a Remote Code Execution (RCE) vulnerability discovered in ChestnutCMS, an open-source content management system. The vulnerability exists in versions 1.5.8 and earlier, allowing remote attackers to execute arbitrary code on the target system through the template creation function. This vulnerability poses a significant risk to organizations using affected versions of ChestnutCMS, as successful exploitation could lead to complete system compromise.

Critical Impact

Remote attackers can execute arbitrary code on vulnerable ChestnutCMS installations through the template creation function, potentially leading to full server compromise, data theft, and lateral movement within the network.

Affected Products

• ChestnutCMS v.1.5.8
• ChestnutCMS versions prior to v.1.5.8

Discovery Timeline

• 2026-02-05 - CVE-2025-70073 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2025-70073

Vulnerability Analysis

This vulnerability falls into the category of Remote Code Execution (RCE) through the template creation functionality in ChestnutCMS. Content management systems often provide template creation features that allow administrators to customize the appearance and behavior of their websites. When these template systems process user-supplied input without proper sanitization, they can become vectors for code injection attacks.

In the case of ChestnutCMS, the template creation function appears to lack sufficient input validation, enabling attackers to inject and execute malicious code on the server. This type of vulnerability is particularly dangerous in CMS platforms because template engines typically have access to server-side resources and can execute code with the privileges of the web application.

Root Cause

The root cause of this vulnerability lies in improper input validation and sanitization within the template creation function. When users create or modify templates, the application fails to adequately validate the input before processing it, allowing malicious code to be injected and subsequently executed. This is a common weakness in template engines that support dynamic code evaluation or server-side template injection (SSTI) patterns.

Attack Vector

The attack vector for this vulnerability is network-based, requiring the attacker to have access to the template creation functionality. The exploitation process typically involves:

1. An attacker gains access to the ChestnutCMS administration interface or any endpoint exposing the template creation function
2. The attacker crafts a malicious template containing code injection payloads
3. When the template is processed by the server, the injected code is executed with the privileges of the web application
4. The attacker can then execute arbitrary commands, access sensitive data, or establish persistent access to the system

The vulnerability can be exploited remotely without requiring prior authentication if the template creation function is accessible to unauthenticated users, or with authentication if the function is protected. For detailed technical information, refer to the GitHub Issue Discussion.

Detection Methods for CVE-2025-70073

Indicators of Compromise

• Unusual template creation or modification activity in ChestnutCMS logs
• Unexpected processes spawned by the web server or application server
• Suspicious outbound network connections from the CMS server
• Modified system files or new files in web-accessible directories
• Authentication anomalies or new administrative accounts

Detection Strategies

• Monitor ChestnutCMS application logs for abnormal template creation requests
• Implement file integrity monitoring on template directories and system files
• Deploy web application firewalls (WAF) with rules to detect code injection patterns in template submissions
• Use endpoint detection and response (EDR) solutions to identify suspicious process execution chains originating from web application processes

Monitoring Recommendations

• Enable verbose logging for the ChestnutCMS template creation module
• Configure alerts for template modifications outside of normal business hours
• Monitor server resource utilization for anomalous spikes that could indicate exploitation
• Implement network traffic analysis to detect command-and-control communications

How to Mitigate CVE-2025-70073

Immediate Actions Required

• Audit all ChestnutCMS installations to identify systems running version 1.5.8 or earlier
• Restrict access to the template creation function to trusted administrators only
• Implement network segmentation to isolate CMS servers from critical infrastructure
• Review existing templates for signs of malicious code injection
• Consider temporarily disabling the template creation feature until a patch is available

Patch Information

As of the current publication date, organizations should monitor the ChestnutCMS GitHub repository for security updates and patch releases. It is recommended to upgrade to the latest version when a fix becomes available and to subscribe to security notifications from the vendor.

Workarounds

• Implement strict access controls on the template creation functionality, limiting it to only essential personnel
• Deploy a web application firewall (WAF) with rules to filter potentially malicious template content
• Apply input validation at the application level by customizing the template processing logic if possible
• Run ChestnutCMS with minimal privileges to limit the impact of successful exploitation
• Consider using containerization or sandboxing to isolate the CMS environment

# Example: Restrict access to template endpoints via nginx
location /admin/template {
    allow 10.0.0.0/8;
    deny all;
    # Only allow access from trusted internal networks
}