CVE-2025-27915

Vulnerability Description

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

CVSS Score

Affected Products

Related Weaknesses (CWE)

References

• https://wiki.zimbra.com/wiki/Security_CenterRelease Notes
• https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_FixesRelease Notes
• https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_FixesRelease Notes
• https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_FixesRelease Notes
• https://strikeready.com/blog/0day-ics-attack-in-the-wild/ExploitThird Party Advisory
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-US Government Resource