CVE-2026-27175

Comprehensive Technical Analysis of CVE-2026-27175

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2026-27175 CVSS Score: 9.8

The vulnerability in MajorDoMo (Major Domestic Module) involves unauthenticated OS command injection via the rc/index.php endpoint. The $param variable from user input is interpolated into a command string without proper sanitization, leading to potential remote code execution (RCE). The command is inserted into a database queue by safe_exec(), which does not perform sanitization. The cycle_execs.php script, accessible without authentication, retrieves and executes these commands.

Severity Evaluation:

• Critical: The CVSS score of 9.8 indicates a critical vulnerability due to the potential for unauthenticated RCE, which can lead to full system compromise.
• Impact: High, as it allows an attacker to execute arbitrary commands on the affected system.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Unauthenticated Access: The cycle_execs.php script is accessible without authentication, allowing any user to trigger the command execution process.
2. Race Condition: An attacker can exploit a race condition by first triggering cycle_execs.php to purge the queue and enter a polling loop, then injecting a malicious command via the rc endpoint while the worker is polling.

Exploitation Methods:

1. Command Injection: The attacker can inject shell metacharacters into the $param variable, which will be executed by the system.
2. Race Condition Exploitation: By carefully timing the injection, the attacker can ensure that the malicious command is executed within one second.

3. Affected Systems and Software Versions

Affected Systems:

• Any system running MajorDoMo with the vulnerable rc/index.php and cycle_execs.php scripts.

Software Versions:

• Specific versions of MajorDoMo that include the vulnerable code. The exact versions can be identified by reviewing the GitHub pull request referenced in the CVE.

4. Recommended Mitigation Strategies

1. Patching:

   • Apply the patch provided in the GitHub pull request (https://github.com/sergejey/majordomo/pull/1177) to sanitize user input properly.

2. Input Validation:

   • Ensure that all user inputs are properly sanitized using functions like escapeshellarg() to prevent command injection.

3. Access Control:

   • Restrict access to the cycle_execs.php script to authenticated users only.
   • Implement proper authentication and authorization mechanisms to prevent unauthorized access.

4. Monitoring and Logging:

   • Implement robust logging and monitoring to detect and respond to suspicious activities.
   • Use intrusion detection systems (IDS) to identify and alert on potential exploitation attempts.

5. Regular Updates:

   • Keep the software up to date with the latest security patches and updates.

5. Impact on Cybersecurity Landscape

Immediate Impact:

• Organizations using MajorDoMo are at high risk of RCE attacks, which can lead to data breaches, system compromises, and other severe security incidents.

Long-Term Impact:

• This vulnerability highlights the importance of proper input validation and sanitization in web applications.
• It underscores the need for continuous monitoring and timely patching of software to mitigate such critical vulnerabilities.

6. Technical Details for Security Professionals

Vulnerability Details:

• The $param variable is interpolated into a command string without sanitization, leading to command injection.
• The safe_exec() function does not perform sanitization, allowing malicious commands to be queued.
• The cycle_execs.php script retrieves and executes these commands without authentication, creating a race condition that can be exploited.

Exploitation Steps:

1. Trigger cycle_execs.php to purge the queue and enter a polling loop.
2. Inject a malicious command via the rc endpoint while the worker is polling.
3. The injected shell metacharacters expand inside double quotes, achieving RCE within one second.

Mitigation Code Example:

// Sanitize user input
$param = escapeshellarg($param);

// Safe execution with sanitized input
safe_exec("command $param");

References:

• Chocapikk Blog Post
• GitHub Pull Request
• VulnCheck Advisory

By addressing this vulnerability promptly and implementing robust security measures, organizations can significantly reduce the risk of exploitation and protect their systems from potential attacks.