CVE-2019-9621VulnerabilityPublished 07/07/2025Updated 10/24/2026
CVE-2019-9621: Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability
Affects Synacor Zimbra Collaboration Suite (ZCS)Source CISA KEV
Severity
HighNo CVSS score published yet
- Exploitation
Actively exploited – in CISA KEV since 07/07/2025
- KEV deadline
- 07/28/2025
- EPSS
- 81.0% chance of exploitation in 30 days – higher than 99% of CVEs
What to do
CISA required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Description
Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery (SSRF) vulnerability via the ProxyServlet component.