A critical zero-day vulnerability in Zimbra Collaboration Suite has been actively exploited by hackers using malicious iCalendar files. This flaw allows attackers to execute arbitrary code remotely, posing a significant threat to organizations relying on Zimbra for email and collaboration services. The exploitation involves specially crafted iCalendar (.ics) files that, when processed by vulnerable Zimbra servers, trigger the flaw and enable unauthorized access or control. Security researchers have identified this zero-day being leveraged in targeted attacks, emphasizing the urgency for administrators to apply patches and mitigate risks. The vulnerability underscores the importance of proactive security measures and timely updates in enterprise communication platforms. This article delves into the technical details of the exploit, the impact on affected systems, and recommended defensive strategies to safeguard against ongoing and future attacks. Organizations are urged to review their Zimbra deployments, monitor for suspicious activity, and implement security best practices to prevent exploitation of this critical zero-day vulnerability.
This Cyber News was published on www.bleepingcomputer.com. Publication date: Sun, 05 Oct 2025 14:45:20 +0000