CVE-2016-3412 in Zimbra Collaboration
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Zimbra Collaboration before 8.7.0 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka bugs 103997, 104413, 104414, 104777, and 104791.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2016-3412 represents a critical security flaw in Zimbra Collaboration software versions prior to 8.7.0, encompassing multiple cross-site scripting vulnerabilities that collectively expose the platform to remote code execution risks. This vulnerability affects the core messaging and collaboration infrastructure, potentially compromising user sessions and sensitive data within enterprise environments that rely on Zimbra for email and calendar services. The affected versions include all releases before the 8.7.0 milestone, making a substantial portion of deployed Zimbra installations susceptible to exploitation. These vulnerabilities were catalogued under multiple bug numbers including 103997, 104413, 104414, 104777, and 104791, indicating the complexity and breadth of the affected components within the Zimbra ecosystem.
The technical implementation of these XSS vulnerabilities stems from insufficient input validation and output encoding mechanisms within the Zimbra web interface. Attackers can exploit these flaws by crafting malicious payloads that are then executed in the context of other users' browsers when they view affected content. The unspecified vectors suggest that multiple entry points within the application's user interface and API endpoints were vulnerable to injection attacks, potentially including email content rendering, calendar event handling, and administrative interface components. This lack of specific vector identification indicates the vulnerabilities were systemic rather than isolated, affecting fundamental data processing and display functions throughout the platform.
The operational impact of CVE-2016-3412 extends beyond simple data theft, as successful exploitation could enable attackers to hijack user sessions, redirect users to malicious websites, or execute arbitrary code within the browser context of authenticated users. Enterprise environments utilizing Zimbra for business-critical communications face significant risks including unauthorized access to sensitive corporate emails, calendar data, and contact information. The remote nature of these vulnerabilities means attackers do not require physical access to the network or local system compromise, making them particularly dangerous in cloud-hosted and distributed deployment scenarios. Organizations may experience data breaches, regulatory compliance violations, and reputational damage as a result of successful exploitation.
Organizations should prioritize immediate remediation through upgrading to Zimbra Collaboration 8.7.0 or later versions that contain the necessary patches for these XSS vulnerabilities. Additional mitigations include implementing strict content security policies, enabling web application firewalls, and conducting thorough security assessments of existing deployments. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in software applications, and represents a clear violation of secure coding practices. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1566 which involves phishing and social engineering through malicious web content, potentially enabling further attack vectors including credential theft and privilege escalation. Regular security monitoring and input validation testing should be implemented to prevent similar vulnerabilities in future deployments and maintain robust security postures across enterprise email infrastructure.