Live › vulnerability › CVE-2026-73570
Go to dashboardUnauthenticated OS command injection in Zimbra's SNMP notification path. A malformed SMTP RCPT TO address is logged to /var/log/zimbra.log. Swatchdog matches it as a 'Service status change' line and passes it to a backticked shell call in dosnmp, so commands run as the zimbra user. It needs the optional zimbra-snmp package with SNMP notifications enabled. It is exploited in the wild (CISA KEV, Aug 21 2026) and public PoCs exist. Microsoft saw web shells, root escalation, credential theft and lateral movement across Zimbra clusters. Fixed in ZCS 10.1.20 (Jul 20 2026); the CVE was disclosed Aug 13.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
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.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| Synacor Zimbra Collaboration Suite (ZCS) | vendor | – | – |
| Zimbra Collaboration Suite (ZCS) | vendor | < 10.1.20 (only with zimbra-snmp installed and SNMP notifications enabled) | 10.1.20 |
| synacor zimbra collaboration suite | vendor | < 10.1.20 | 10.1.20 |
zmcontrol -v as the zimbra user; anything below 10.1.20 is affecteddpkg -l zimbra-snmp or rpm -q zimbra-snmp)su - zimbra -c "zmprov gs $(zmhostname) zimbraServiceEnabled" and look for snmp)Service status change with $( or backticks, unexpected JSP files under the Zimbra webroot, and a zimlog.service systemd unit10.1.20 or later (10.1.21 is out as of Sep 24 2026)zmswatchctl stop and zmprov ms $(zmhostname) -zimbraServiceEnabled snmpEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
Zimbra Collaboration Suite (ZCS) contains an OS command injection vulnerability which could allow an unauthenticated attacker to send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.
CISA required action: 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.
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