CVE-2024-45516 in Zimbra Collaboration Suite
Summary
by MITRE • 05/14/2025
An issue was discovered in Zimbra Collaboration (ZCS) 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, including malformed <img> tags with embedded JavaScript. The vulnerability is triggered when a user views a specially crafted email in the Classic UI, requiring no additional user interaction.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/12/2025
The vulnerability identified as CVE-2024-45516 represents a critical cross-site scripting flaw within Zimbra Collaboration Suite versions prior to specific patch releases. This security weakness exists in the Zimbra Classic UI component and demonstrates how inadequate input validation can create persistent attack vectors for malicious actors. The vulnerability affects multiple version streams including ZCS 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47, indicating a widespread exposure across the product's lifecycle. The flaw specifically manifests when users view specially crafted emails containing malicious HTML content, making it particularly dangerous in enterprise environments where email is a primary communication channel.
The technical root cause of this vulnerability stems from insufficient sanitization of HTML content within the Classic UI rendering engine. Attackers can exploit this weakness by embedding malformed <img> tags that contain embedded JavaScript code within their src attributes or other HTML properties. The vulnerability operates through the standard email viewing process where the email client processes and renders HTML content without proper validation of potentially malicious markup. This particular implementation flaw allows attackers to bypass existing security controls that should prevent execution of arbitrary scripts within user sessions. The vulnerability is classified under CWE-79 as a classic cross-site scripting issue, which specifically addresses the improper handling of untrusted data in web applications. The attack vector requires no additional user interaction beyond simply viewing the malicious email, making it particularly dangerous for phishing campaigns and social engineering attacks.
The operational impact of CVE-2024-45516 extends beyond simple script execution to potentially enable complete session hijacking and unauthorized access to sensitive corporate data. When a victim views the malicious email, the embedded JavaScript code executes within their browser session, potentially allowing attackers to steal session cookies, access mailbox contents, or perform actions on behalf of the authenticated user. This vulnerability could facilitate data exfiltration, privilege escalation, and persistent access to corporate email systems. The attack scenario becomes particularly concerning in environments where users have administrative privileges or access to sensitive information, as the successful exploitation could lead to complete compromise of email infrastructure. Organizations relying on Zimbra Classic UI for email services face significant risk of unauthorized access, data leakage, and potential lateral movement within their network infrastructure.
Mitigation strategies for CVE-2024-45516 require immediate patching of affected Zimbra versions to the latest available releases. Organizations should prioritize updating their Zimbra installations to versions containing the security fixes for this vulnerability. System administrators should also implement additional defensive measures including enhanced email filtering, content security policies, and web application firewalls to detect and prevent malicious email content from reaching user inboxes. The implementation of CSP headers and proper HTML sanitization in web applications can provide additional layers of protection against similar vulnerabilities. Security teams should monitor for indicators of compromise including unusual email traffic patterns, unauthorized access attempts, and suspicious session activities. Regular security assessments and vulnerability scanning should be conducted to identify any remaining exposure points within the email infrastructure. The ATT&CK framework categorizes this vulnerability under T1566 as a phishing technique, with potential for T1078 for valid accounts usage, highlighting the multi-stage nature of attacks that could exploit this weakness. Organizations should also consider implementing user awareness training to help identify and report suspicious email content that might attempt to exploit this or similar vulnerabilities.