Zimbra ZCS 8.8.15-10.1 Classic UI XSS (CVE-2025-48700)
CVE-2025-48700 Published on June 23, 2025
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.
Known Exploited Vulnerability
This Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that could allow attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information.
The following remediation steps are recommended / required by April 23, 2026: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Analysis
CVE-2025-48700 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2025-48700 has been classified to as a XSS vulnerability or weakness.
Products Associated with CVE-2025-48700
Want to know whenever a new CVE is published for Synacor Zimbra Collaboration Suite? stack.watch will email you.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.