CVE-2023-24031 in Zimbra Collaboration
Summary
by MITRE • 06/16/2023
An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 8.8.15. XSS can occur, via one of attributes of the webmail /h/ endpoint, to execute arbitrary JavaScript code, leading to information disclosure.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2023-24031 represents a critical cross-site scripting flaw within Zimbra Collaboration Suite versions 8.8.15 and 9.0. This security weakness exists within the webmail /h/ endpoint of the Zimbra platform, creating a pathway for malicious actors to inject and execute arbitrary JavaScript code in the context of a victim's browser session. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it within the web interface. This particular flaw falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS variant where the malicious payload can persist and affect multiple users who interact with the vulnerable endpoint. The vulnerability's impact extends beyond simple script execution to include potential information disclosure, as attackers can leverage the executed JavaScript to access sensitive data within the user's session context.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input parameters that are passed through the webmail /h/ endpoint without proper sanitization. The flaw allows for arbitrary JavaScript code injection through specific attributes of this endpoint, enabling attackers to execute malicious scripts in the browser of authenticated users. This creates a persistent threat vector where victims who access the compromised endpoint may unknowingly execute the injected code, potentially leading to session hijacking, credential theft, or further escalation within the target environment. The vulnerability's severity is amplified by the fact that it affects widely deployed versions of Zimbra Collaboration Suite, making it a prime target for automated exploitation campaigns. The attack chain typically involves initial access through social engineering or compromised credentials, followed by the delivery of malicious payloads through the vulnerable endpoint, which then executes in the context of the victim's browser session.
The operational impact of CVE-2023-24031 extends significantly beyond immediate code execution capabilities, as it creates persistent security risks for organizations relying on Zimbra Collaboration Suite for email services. Successful exploitation can lead to unauthorized access to sensitive email communications, user credentials, and personal information stored within the Zimbra environment. The vulnerability's persistence means that once exploited, malicious scripts can continue to execute against all users who interact with the affected endpoint, potentially enabling long-term surveillance and data exfiltration operations. Organizations may face regulatory compliance violations, reputational damage, and potential legal consequences due to unauthorized data access. The attack surface is particularly concerning given that Zimbra is commonly used in enterprise environments where sensitive business communications and personal data are routinely processed, making the potential for widespread impact substantial. The vulnerability also creates opportunities for attackers to establish persistent access points within the network, potentially serving as a foothold for further lateral movement and privilege escalation activities.
Organizations should implement immediate mitigations including applying the latest security patches from Zimbra, implementing web application firewalls to detect and block malicious payloads, and conducting comprehensive security assessments of their Zimbra deployments. Input validation and output encoding mechanisms should be strengthened to prevent similar vulnerabilities from occurring in other parts of the application. Network segmentation and monitoring solutions should be deployed to detect anomalous behavior associated with XSS attacks. The vulnerability's classification under ATT&CK technique T1059.007 for scripting and T1566 for social engineering highlights the need for both technical and user awareness training programs. Regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities across the entire application stack. The implementation of Content Security Policy headers can provide additional protection against XSS attacks by restricting the sources from which scripts can be executed within the browser context. Organizations should also consider implementing multi-factor authentication and privileged access management controls to limit the potential impact of successful exploitation attempts.