EUVD-2025-21398

Comprehensive Technical Analysis of EUVD-2025-21398

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-21398 affects the XWiki Rendering system, specifically in versions starting from 4.2-milestone-1 up to 13.10.11, 14.4.7, and 14.10. The issue arises from the default macro content parser not preserving the restricted attribute of the transformation context when executing nested macros. This flaw allows the execution of macros that are normally forbidden in restricted mode, including script macros.

Severity Evaluation:

• CVSS Base Score: 10.0
• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

The CVSS score of 10.0 indicates a critical vulnerability. The high severity is due to the potential for unauthorized access, data breaches, and system compromise. The attack vector (AV:N) is network-based, requiring low complexity (AC:L) and low privileges (PR:L) to exploit. The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H), and the scope is changed (S:C), meaning the vulnerability can affect components beyond the initial compromised system.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Untrusted User Input: An attacker could exploit this vulnerability by injecting malicious macros into the XWiki system through untrusted user input.
• Nested Macros: The vulnerability allows nested macros to bypass the restricted mode, enabling the execution of forbidden macros, including script macros.

Exploitation Methods:

• Script Injection: Attackers can inject script macros that execute arbitrary code, leading to remote code execution (RCE).
• Data Exfiltration: Malicious macros can be used to exfiltrate sensitive data from the XWiki system.
• System Compromise: Execution of unauthorized macros can lead to full system compromise, including unauthorized access and data manipulation.

3. Affected Systems and Software Versions

Affected Versions:

• XWiki Rendering versions from 4.2-milestone-1 to 13.10.11
• XWiki Rendering versions 14.5 to 14.10
• XWiki Rendering versions 14.0 to 14.4.7

Patched Versions:

• XWiki 13.10.11
• XWiki 14.4.7
• XWiki 14.10

4. Recommended Mitigation Strategies

Immediate Mitigation:

• Disable Comments for Untrusted Users: Until the system is upgraded to a patched version, disable comments for untrusted users to prevent the injection of malicious macros.
• Monitor and Audit: Implement strict monitoring and auditing of user activities to detect and respond to any suspicious behavior.

Long-Term Mitigation:

• Upgrade to Patched Versions: Upgrade to the patched versions of XWiki (13.10.11, 14.4.7, or 14.10) as soon as possible.
• Regular Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate similar issues.
• Input Validation: Enforce strict input validation and sanitization to prevent the injection of malicious content.

5. Impact on European Cybersecurity Landscape

The vulnerability in XWiki Rendering poses a significant risk to organizations using the affected versions, particularly those in the European Union. The potential for data breaches, unauthorized access, and system compromise can have severe implications for data privacy, compliance with regulations such as GDPR, and overall cybersecurity posture. Organizations must prioritize patching and implementing robust security measures to mitigate the risk.

6. Technical Details for Security Professionals

Vulnerability Details:

• Root Cause: The default macro content parser fails to preserve the restricted attribute of the transformation context when executing nested macros.
• Affected Components: The cache and chart macros bundled in XWiki use the vulnerable feature.
• Exploitation: Attackers can exploit this vulnerability by injecting nested macros that bypass the restricted mode, allowing the execution of forbidden macros.

Detection and Response:

• Log Analysis: Analyze logs for any unusual macro execution or script injection attempts.
• Intrusion Detection Systems (IDS): Implement IDS rules to detect and alert on suspicious macro execution patterns.
• Incident Response: Develop an incident response plan to quickly identify, contain, and remediate any exploitation attempts.

References:

• GitHub Security Advisory
• GitHub Commit
• Jira Issue
• Jira Issue

By addressing this vulnerability promptly and effectively, organizations can significantly reduce the risk of exploitation and ensure the security and integrity of their XWiki systems.