CVE-2023-45206 in Zimbra Collaboration Suite
Summary
by MITRE • 02/13/2024
An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15, 9.0, and 10.0. Through the help document endpoint in webmail, an attacker can inject JavaScript or HTML code that leads to cross-site scripting (XSS). (Adding an adequate message to avoid malicious code will mitigate this issue.)
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Analysis
by VulDB Data Team • 02/09/2026
The vulnerability identified as CVE-2023-45206 affects Zimbra Collaboration Suite versions 8.8.15, 9.0, and 10.0, representing a critical cross-site scripting flaw that undermines the security of the webmail interface. This issue resides within the help document endpoint of the Zimbra webmail application, where improper input validation allows attackers to inject malicious JavaScript or HTML code directly into the user interface. The vulnerability stems from insufficient sanitization of user-supplied data when rendering help documentation, creating an environment where malicious payloads can be executed in the context of authenticated users' browsers.
The technical exploitation of this vulnerability occurs through the webmail help system, which serves as an entry point for attackers to inject malicious code that persists in the help documents. When legitimate users access the help content, their browsers execute the injected JavaScript code, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. This XSS vulnerability operates at the client-side level, where the malicious code executes within the user's browser context, making it particularly dangerous as it can leverage the authenticated user's privileges. The flaw aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications.
The operational impact of this vulnerability extends beyond simple data theft, as it can enable attackers to establish persistent access to user accounts and compromise the integrity of the email system. An attacker could inject code that redirects users to phishing sites, steals session cookies, or modifies email content, potentially leading to significant data breaches and unauthorized access to sensitive corporate communications. The vulnerability affects the core webmail functionality of Zimbra, which serves as a primary communication channel for organizations, making it a high-value target for threat actors. This issue particularly impacts enterprise environments where Zimbra is deployed as a collaboration platform, as it can compromise the security of entire email domains.
Organizations utilizing affected Zimbra versions should implement immediate mitigations including input validation and output encoding for all help document content, along with comprehensive security monitoring of user sessions. The recommended approach involves adding adequate message validation to prevent malicious code injection, which aligns with ATT&CK technique T1059.007 for command and scripting interpreter. Additional protective measures include implementing content security policies, disabling unnecessary help document features, and conducting thorough security audits of web application inputs. Regular updates and patches should be applied immediately upon availability, as this vulnerability represents a significant risk to email security and user privacy. The security implications extend to potential lateral movement within networks, as compromised email accounts often provide access to other corporate systems and resources.