CVE-2026-25763

Comprehensive Technical Analysis of CVE-2026-25763

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2026-25763 CVSS Score: 9.9

The vulnerability in OpenProject, an open-source, web-based project management software, allows for arbitrary file write due to improper handling of user input in the repository changes endpoint. This vulnerability is classified as critical with a CVSS score of 9.9, indicating a high risk to systems running affected versions of OpenProject.

Severity Evaluation:

• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The severity is justified by the potential for remote code execution (RCE), which can lead to full system compromise, including unauthorized access to sensitive files and the ability to execute arbitrary commands on the target host.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Unauthenticated Users: If the repository browsing permission is granted to unauthenticated users, the vulnerability can be exploited without any authentication.
• Authenticated Users: Users with the :browse_repository permission can exploit this vulnerability.

Exploitation Methods:

1. Command Injection: An attacker can inject Git command-line options by supplying a specially crafted rev value (e.g., rev=--output=/tmp/poc.txt).
2. Arbitrary File Write: The injected command causes Git to write output to an attacker-chosen path, allowing the creation or overwriting of arbitrary files.
3. Remote Code Execution (RCE): By crafting custom commits, an attacker can upload valid shell scripts, leading to RCE. This can result in the creation of a reverse shell or the execution of other malicious commands.

3. Affected Systems and Software Versions

Affected Versions:

• OpenProject versions prior to 16.6.7
• OpenProject versions prior to 17.0.3

Unaffected Versions:

• OpenProject 16.6.7 and later
• OpenProject 17.0.3 and later

4. Recommended Mitigation Strategies

Immediate Actions:

1. Upgrade Software: Upgrade to OpenProject version 16.6.7 or 17.0.3, which include the patch for this vulnerability.
2. Restrict Permissions: Limit the :browse_repository permission to trusted users only.
3. Monitor Logs: Monitor system and application logs for any suspicious activity related to Git commands and file writes.

Long-Term Strategies:

1. Regular Patching: Implement a regular patching and update schedule for all software.
2. Input Validation: Ensure robust input validation and sanitization for all user-supplied data.
3. Security Audits: Conduct regular security audits and code reviews to identify and mitigate similar vulnerabilities.

5. Impact on Cybersecurity Landscape

This vulnerability highlights the critical importance of input validation and secure coding practices in web applications. The potential for RCE and the ability to compromise the entire system underscore the need for vigilant security measures, especially in open-source projects where the codebase is publicly accessible.

Broader Implications:

• Supply Chain Security: Open-source projects are widely used, and vulnerabilities in such projects can have a cascading effect on the broader software ecosystem.
• Incident Response: Organizations need to have robust incident response plans to quickly address and mitigate such critical vulnerabilities.
• User Awareness: Increased awareness among users and administrators about the risks associated with granting broad permissions and the importance of timely updates.

6. Technical Details for Security Professionals

Vulnerability Details:

• Endpoint: /projects/:project_id/repository/changes
• Parameter: rev
• Exploit: Injecting Git command-line options via the rev parameter (e.g., rev=--output=/tmp/poc.txt).

Exploitation Steps:

1. Crafted Input: Supply a specially crafted rev value to the repository changes endpoint.
2. Git Command Execution: OpenProject executes the SCM command with the injected options.
3. File Write: Git writes the output to the specified path, allowing for arbitrary file creation or overwriting.
4. RCE: By crafting custom commits, an attacker can upload valid shell scripts, leading to RCE and potential reverse shell creation.

Detection and Mitigation:

• Log Analysis: Look for unusual Git command executions and file writes in system logs.
• Network Monitoring: Monitor for outbound connections that may indicate a reverse shell.
• Access Controls: Implement strict access controls and regularly review user permissions.

Conclusion: CVE-2026-25763 is a critical vulnerability that underscores the importance of secure coding practices and regular software updates. Organizations using OpenProject should prioritize upgrading to the patched versions and implement robust security measures to mitigate similar risks in the future.