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CVE-2024-27443: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability
Synacor Zimbra Collaboration Suite (ZCS) · in CISA KEV since 2025-05-19
2025-05-19added to KEV
2025-06-09federal remediation due date
23.63%EPSS exploit probability (30 days) 97.7th percentile
6.1 MEDIUMCVSS 3.1
Unknownknown ransomware use
280days from NVD publication to KEV
What it is
Zimbra Collaboration contains a cross-site scripting (XSS) vulnerability in the CalendarInvite feature of the Zimbra webmail classic user interface. An attacker can exploit this vulnerability via an email message containing a crafted calendar header, leading to the execution of arbitrary JavaScript code.
Required action (CISA)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
| CWE | CWE-79 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD published | 2024-08-12 (Analyzed) |
Original records: NVD · CISA KEV · JSON: /api/cve/CVE-2024-27443.json · all KEV CVEs
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Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.