CVE-2025-27915
Description
Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that 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 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.
CISA KEV
- Vendor
- Synacor
- Product
- Zimbra Collaboration Suite (ZCS)
- Due date
- 2025-10-28
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: cisa-kev — https://wiki.zimbra.com/wiki/Security_Center ; https://nvd.nist.gov/vuln/detail/CVE-2025-27915
Exploits
References
Verify integrity in audit chain (admin only). AS-IS.