Executive Summary

CVE-2026-30643 is a vulnerability in DedeCMS version 5.7.118 that allows attackers with backend access to execute arbitrary PHP code on the server.

The issue arises from the module upload functionality where authenticated users can upload crafted XML module files containing a base64-encoded PHP payload inside a <setup> tag.

During module installation, this payload is decoded and written to a PHP file on the server, which is then included and executed, enabling remote code execution.

• Attackers log into the backend, upload a malicious XML module, trigger the installation, and then execute arbitrary commands via the created PHP file.

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Impact Analysis

This vulnerability can lead to remote code execution on the affected server, allowing attackers to run arbitrary system commands.

An attacker with backend access could gain full control over the server, potentially leading to data theft, server compromise, defacement, or further attacks within the network.

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Detection Guidance

This vulnerability can be detected by checking for the presence of suspicious PHP files created in the data/module/ directory, specifically files named with a hash followed by '-setup.php'. These files are generated when a crafted module XML with a base64-encoded PHP payload is uploaded and executed.

You can also monitor web server access logs for requests to URLs like data/module/<hash>-setup.php with query parameters such as ?cmd=whoami, which indicate attempts to execute arbitrary commands.

Suggested commands to detect exploitation attempts or presence of malicious files include:

• List suspicious PHP files in the module data directory: ls -l data/module/*-setup.php
• Search web server logs for access to these PHP files: grep 'data/module/.*-setup.php' /var/log/apache2/access.log
• Check for recent file creation or modification times in the data/module directory: find data/module/ -name '*-setup.php' -mtime -7
• If you have backend access, review uploaded module XML files for suspicious base64-encoded <setup> tags containing PHP code.

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Mitigation Strategies

Immediate mitigation steps include restricting backend access to trusted users only, as exploitation requires authenticated backend login.

Disable or restrict the module upload and installation functionality if it is not needed.

Monitor and remove any suspicious PHP files in the data/module/ directory, especially those matching '*-setup.php'.

Implement strict input validation and sanitization on uploaded module XML files to prevent execution of arbitrary PHP code.

If possible, update DedeCMS to a version that patches this vulnerability once available.

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Compliance Impact

The vulnerability in DedeCMS 5.7.118 allows authenticated attackers to execute arbitrary PHP code on the server via crafted module uploads, leading to remote code execution.

Such unauthorized code execution can lead to unauthorized access, data breaches, and potential manipulation or exfiltration of sensitive data.

This can negatively impact compliance with common standards and regulations like GDPR and HIPAA, which require protection of personal and sensitive data against unauthorized access and breaches.

Organizations using vulnerable versions of DedeCMS may face increased risk of non-compliance due to potential data compromise stemming from exploitation of this vulnerability.

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