CVE-2026-73570—Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

Vulnerability Name

Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability

Description

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.

Known To Be Used in Ransomware Campaigns?

Ransomware Status:

Unknown

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.

Additional Notes

• https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
• https://blog.zimbra.com/2026/07/patch-release-update-zimbra-10-1-20/
• BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
• Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
• https://nvd.nist.gov/vuln/detail/CVE-2026-73570

Related Weaknesses

• CWE-78