A Local File Inclusion (LFI) vulnerability exists in the Webmail Classic UI of Zimbra Collaboration (ZCS) 10.0 and 10.1 because of improper handling of user-supplied request parameters in the RestFilter servlet. This vulnerability allows an unauthenticated remote attacker to craft requests to the /h/rest endpoint to influence internal request dispatching, allowing inclusion of arbitrary files from the WebRoot directory. With a CVSS score of 8.8, this high-severity vulnerability poses significant risks to affected systems.
Risk to organizations includes unauthorized access to sensitive files and the potential for further exploitation of their systems. Given the critical nature of this vulnerability, organizations should prioritize patching immediately. As of now, confirmed exploits exist, indicating that attackers may leverage this vulnerability to compromise systems.
Organizations using affected versions of the Zimbra Collaboration Suite should take immediate action. The presence of known exploits in the wild heightens the urgency for defenders to apply the necessary patches to mitigate potential attacks.
The Zimbra Collaboration Suite has been added to the Known Exploited Vulnerabilities (KEV) catalog, emphasizing the need for swift remediation efforts. Organizations must remain vigilant and proactive against this and similar vulnerabilities.
Vulnerability Details
The vulnerability allows for Local File Inclusion, classified under CWE-98. The affected versions are ZCS 10.0 and 10.1 due to improper parameter handling in the RestFilter servlet. The vulnerability was published on December 22, 2025, and has a CVSS score of 8.8, indicating a high severity level.
Technical Analysis
The root cause of this vulnerability lies in the improper validation of user-supplied inputs within the Zimbra Collaboration Suite’s RestFilter servlet. This creates an opportunity for attackers to perform LFI attacks by supplying crafted requests to the /h/rest endpoint.
The attack vector is network-based, requiring low complexity and no privileges, but does require user interaction. The impact on confidentiality, integrity, and availability is high, as attackers could potentially access sensitive files, modify data, or disrupt services.
Risk & Impact Analysis
The deployment of the Zimbra Collaboration Suite in various organizational environments increases the potential blast radius of this vulnerability. Attackers can exploit the LFI vulnerability to gain unauthorized access to files and potentially escalate their privileges within the system.
The urgency for organizations to address this vulnerability is underscored by its inclusion in the KEV catalog. Organizations should assess their exposure and prioritize remediation based on the CVSS score and the potential impact of exploitation.
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
The affected products include Zimbra Collaboration Suite versions 10.0.0 to 10.0.17 and 10.1.0 to 10.1.12. Organizations should ensure they are running the latest patched versions to mitigate this vulnerability.
Mitigation & Remediation
Organizations should apply the vendor's patches as soon as they become available. If a patch is unavailable, consider implementing configuration hardening measures, such as restricting access to the /h/rest endpoint, and monitor logs for any suspicious activity.
For further guidance on implementing effective security measures, organizations can refer to the penetration testing services offered by AppSecure.
Detection Guidance
Organizations should monitor their systems for unusual log entries, particularly those targeting the /h/rest endpoint. Behavioral anomalies in user activity should also be flagged for review.
AppSecure Threat Intelligence Insight
The presence of a Local File Inclusion vulnerability in widely used software like the Zimbra Collaboration Suite signifies a need for organizations to review their security postures. This vulnerability reflects ongoing trends in web application security, wherein improper input validation leads to severe consequences.
To strengthen defenses, organizations should adopt a comprehensive security strategy that includes regular vulnerability assessments and timely patch management. By prioritizing security, organizations can better safeguard their assets against evolving threats.
For additional insights on improving security management practices, organizations are encouraged to explore resources such as the vulnerability management program and the penetration testing methodology outlined by AppSecure.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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