Description
An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. 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, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.
CISA Known Exploited Vulnerability
Date added 2026-04-20 | Due date 2026-04-23
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
References
www.cisa.gov/...erabilities-catalog?field_cve=CVE-2025-48700
wiki.zimbra.com/wiki/Zimbra_Security_Advisories
wiki.zimbra.com/wiki/Security_Center
wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy