CVE intelligenceCISA KEV

CVE-2026-73570

Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

Published Aug 13, 2026Sources checked Sep 12, 2026

8.9HIGHCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-73570 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Synacor Zimbra Collaboration Suite (ZCS).

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA KEVListedObserved exploitation

EPSS32.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-73570?

A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20 when the optional zimbra-snmp package is installed and SNMP notifications are enabled. Due to improper sanitization of untrusted input during SNMP notification processing, an unauthenticated attacker can send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.