CVE-2016-3411 in Zimbra Collaboration
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Zimbra Collaboration before 8.7.0 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka bug 103609.
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Analysis
by VulDB Data Team • 05/13/2026
The CVE-2016-3411 vulnerability represents a critical cross-site scripting flaw discovered in Zimbra Collaboration software versions prior to 8.7.0, specifically identified as bug 103609 within the Zimbra ecosystem. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a fundamental web application security weakness that enables attackers to inject malicious scripts into web pages viewed by other users. The vulnerability exists in the Zimbra Collaboration Suite's web interface handling of user input, creating a pathway for remote attackers to execute arbitrary web scripts or HTML code within the context of other users' browsers. The unspecified vectors suggest that the flaw could potentially manifest through multiple input points within the application's user interface, including but not limited to email content processing, web form submissions, or dynamic content generation mechanisms.
The technical exploitation of this vulnerability enables attackers to craft malicious payloads that, when executed in a victim's browser, can perform unauthorized actions on behalf of the user. This includes stealing session cookies, modifying user interface elements, redirecting users to malicious sites, or executing arbitrary commands within the application's context. The vulnerability's impact extends beyond simple script injection as it can be leveraged to establish persistent malicious presence within the Zimbra environment, potentially leading to complete compromise of user accounts and access to sensitive email communications. Attackers can exploit this weakness by crafting specially formatted input that bypasses existing security controls and gets rendered as executable code within the browser context of authenticated users.
The operational consequences of this vulnerability are severe for organizations relying on Zimbra Collaboration Suite, as it creates a persistent threat vector that can be exploited without requiring authentication to the target system. Once exploited, attackers can access all email accounts within the compromised user's permissions, potentially gaining access to confidential business communications, personal data, and sensitive organizational information. The vulnerability's remote nature means that attackers can exploit it from anywhere on the internet, making it particularly dangerous for organizations with remote workers or public-facing email services. This weakness undermines the fundamental security model of the web application, allowing attackers to hijack user sessions and potentially escalate privileges within the Zimbra environment.
Organizations should immediately implement comprehensive mitigation strategies including updating to Zimbra Collaboration Suite version 8.7.0 or later, which contains the necessary patches to address this vulnerability. Additional protective measures should include implementing robust input validation and output encoding mechanisms, deploying web application firewalls to monitor for suspicious script injection attempts, and conducting regular security assessments of the email infrastructure. The mitigation approach should align with industry best practices such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks, emphasizing defense-in-depth strategies that combine multiple layers of security controls. Security teams should also establish monitoring procedures to detect potential exploitation attempts and maintain detailed audit logs of user activities within the Zimbra environment to facilitate incident response and forensic analysis when vulnerabilities are exploited.