CVE-2016-3402 in Zimbra Collaboration
Summary
by MITRE
Unspecified vulnerability in Zimbra Collaboration before 8.7.0 allows remote attackers to affect confidentiality via unknown vectors, aka bug 99167.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2016-3402 affects Zimbra Collaboration software versions prior to 8.7.0, representing a significant security weakness that could compromise the confidentiality of sensitive data. This unspecified vulnerability falls under the broader category of information disclosure flaws that can have severe implications for organizations relying on email and collaboration platforms. The vulnerability was tracked as bug 99167 within Zimbra's internal tracking system, indicating that it was recognized and documented by the vendor's security team. Such undisclosed nature of the specific attack vectors makes this vulnerability particularly concerning as it allows threat actors to potentially exploit the weakness without clear indicators of how the attack might occur.
The technical nature of this vulnerability suggests an issue within the Zimbra Collaboration platform's handling of data processing or access controls that could enable unauthorized parties to gain access to confidential information. While the exact technical mechanism remains unspecified in the CVE description, such vulnerabilities typically involve flaws in authentication mechanisms, data encryption handling, or access control enforcement. The unspecified nature of the vectors indicates that the vulnerability could potentially be exploited through multiple attack paths, making it more difficult for administrators to implement targeted defenses. This type of vulnerability often stems from inadequate input validation, improper access control implementation, or flawed cryptographic operations within the application's core components.
From an operational standpoint, this vulnerability could have substantial impact on organizations using Zimbra Collaboration software, particularly those handling sensitive corporate communications, personal data, or regulated information. Remote attackers could potentially exploit this vulnerability to access confidential emails, calendar data, contact information, or other collaborative content stored within the Zimbra environment. The confidentiality impact suggests that attackers might be able to read or extract data without necessarily modifying it, but the potential for data exfiltration remains significant. Organizations with extensive email infrastructure relying on Zimbra could face regulatory compliance issues, reputational damage, and potential financial losses if this vulnerability is exploited successfully.
The remediation approach for this vulnerability centers on upgrading to Zimbra Collaboration version 8.7.0 or later, which would contain the necessary patches and fixes to address the underlying security flaw. Organizations should prioritize this upgrade as part of their vulnerability management strategy, ensuring that all instances of the affected software are updated to the patched version. Additionally, administrators should conduct thorough testing of the updated environment to ensure compatibility with existing configurations and workflows. Security monitoring should be enhanced to detect any unusual access patterns or potential exploitation attempts during the transition period. The vulnerability aligns with CWE-200, which covers "Information Exposure," and could potentially map to ATT&CK techniques related to credential access and data extraction. Organizations should also review their network segmentation and access controls to minimize potential impact if exploitation occurs, implementing additional monitoring and logging capabilities to detect unauthorized access attempts.