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Limited ExploitationCVE-2024-27443Public Exploit

Zimbra Collaboration - XSS (CVE-2024-27443)

PublishedAug 12, 2024
First SeenN/A
Last Seen
Reported
CVSS6.1
Zimbra
ZimbraZimbra Collaboration
web_applicationenterprise_software

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.

psychologyCrowdSec Analysis

CVE-2024-27443 is a cross-site scripting (XSS) vulnerability in the CalendarInvite feature of Zimbra Collaboration Suite (ZCS) versions 9.0 and 10.0. By sending a specially crafted email with a malicious calendar header, attackers can execute arbitrary JavaScript in the victim's browser when the message is viewed in the classic webmail interface. This flaw could be exploited to steal session cookies, impersonate users, or perform unauthorized actions within the victim's session.

CrowdSec has been tracking this vulnerability and its exploits since 26th of November 2025.

CrowdSec has not observed any significant exploitation activity targeting CVE-2024-27443 across its network. As a result, no community-driven trend analysis is available for this vulnerability at this time.

Attackers exploit this vulnerability by sending crafted calendar invites via email to Zimbra users, embedding malicious scripts in calendar headers to trigger XSS when the invite is viewed in the classic webmail interface. The targeted endpoint is the CalendarInvite feature within Zimbra Collaboration Suite versions 9.0 and 10.0.

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EventDate
CVE Published2024-08-12
CISA KEV2025-05-19
CISA Remediation Deadline2025-06-09
Rule Released2025-11-26

Related Weaknesses

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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External References