CVE-2024-27443

MediumActively exploited (CISA KEV)

Description

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists in the CalendarInvite feature of the Zimbra webmail classic user interface, because of improper input validation in the handling of the calendar header. An attacker can exploit this via an email message containing a crafted calendar header with an embedded XSS payload. When a victim views this message in the Zimbra webmail classic interface, the payload is executed in the context of the victim's session, potentially leading to execution of arbitrary JavaScript code.

SeverityMedium
CVSS6.1
Exploit probability—
ProductSynacor Zimbra Collaboration Suite (ZCS)
PublishedAug 12, 2024
First seenAug 12, 2024
Added to KEVMay 19, 2025

How to fix

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA due date: Jun 9, 2025
Update
  • zimbra collaboration10.0.7 or later

Affected products

ProductAffected versionsFixed in
zimbra collaboration10.0.0 ≤ v < 10.0.7, 9.0.010.0.7

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CVE-2024-27443 · Synacor Zimbra Collaboration Suite (ZCS) · Dark Radar