ACTIVELY EXPLOITED
CVE-2026-73570: Zimbra Collaboration Suite (ZCS) OS Command Injection Vulnerability
| Vendor | Synacor |
|---|---|
| Product | Zimbra Collaboration Suite (ZCS) |
| Actively exploited | Yes |
| Added to CISA KEV | 21 Aug 2026 |
| CISA federal deadline | 24 Aug 2026 |
| Weakness (CWE) | CWE-78 |
Required action (CISA's text)
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.
Description (NVD)
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.
SOURCES
Other Synacor flaws
- CVE-2025-48700: Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability
- CVE-2025-66376: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
- CVE-2020-7796: Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery Vulnerability
- CVE-2025-68645: Synacor Zimbra Collaboration Suite (ZCS) PHP Remote File Inclusion Vulnerability
- CVE-2025-27915: Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.