CVE-2026-73570
Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability
Exploited in the wild
This vulnerability is on the CISA Known Exploited Vulnerabilities list, added 2026-08-21. Federal due date: 2026-08-24.
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.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Zimbra | Collaboration | before 10.1.20 |
| Synacor | Zimbra Collaboration Suite | before 10.1.20 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- CISA KEV catalog
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- https://wiki.zimbra.com/wiki/Security_Center
- https://moje.cert.pl/komunikaty/2026/145/aktywnie-wykorzystywana-podatnosc-w-zimbra-collaboration-suite/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-73570