Critical Zimbra Flaw Could Let Crafted Emails Run Malicious Code in User Sessions
Zimbra is urging customers to apply updates to address a critical security vulnerability impacting the Classic Web Client that could result in arbitrary code execution. The vulnerability has been described as a case of stored cross-site scripting (XSS) that could allow specially crafted emails to execute malicious scripts in a user's session. It has yet to be assigned a CVE identifier. "The update fixes a security issue in the Classic Web Client where a specially crafted email could run malicious code when the email is opened," Zimbra said . "If exploited, it could allow access to mailbox information, session data, or account settings." XSS vulnerabilities occur when an application includes untrusted data in a web page without proper validation or escaping. This allows attackers to inject and execute malicious JavaScript in victims' browsers, which can result in session hijacking, credential theft, and account compromise. Stored XSS, or persistent ...
î Jul 11, 2026