Critical CVSS 8.9 Actively exploited
CVE-2026-73570
Synacor Zimbra Collaboration Suite (ZCS)
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.
What this means
- Exposure
- Exploitable remotely over the network, without authentication and with no action from the victim. The attack does require particular conditions, which makes it less systematic.
- Impact
- An attacker can read sensitive data, modify or destroy data and degrade the service. The impact spreads beyond the vulnerable component into other parts of the system.
- Weakness
- Unfiltered input reaches the system shell, letting the attacker run their own commands on the server.
- Likelihood
- Exploitation is not hypothetical: CISA has observed it in the wild.
What to doTop priority: CISA sets the remediation deadline at 24 August 2026. Start with the instances exposed to the internet.
Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.