CVE-2025-27915
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.
Actively exploited
- In the CISA exploited-vulnerabilities catalogue since Oct 7, 2025
- US federal agencies must remediate it by Oct 28, 2025 (BOD 22-01)
- First attack observed 201 days after disclosure
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Source: CISA KEV · Jul 23, 2026 Jan 20, 2026 Nov 25, 2025 Nov 7, 2025 Oct 7, 2025 Sep 30, 2025
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NAffected products
| Vendors | Prodotto | Versioni |
|---|---|---|
| synacor | zimbra collaboration suite | < 10.0.13 |
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