ACTIVELY EXPLOITED

CVE-2019-9621: Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability

Facts
VendorSynacor
ProductZimbra Collaboration Suite (ZCS)
Actively exploitedYes
Added to CISA KEV7 Jul 2025
CISA federal deadline28 Jul 2025
Weakness (CWE)CWE-807, CWE-918

Required action (CISA's text)

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 (NVD)

Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery (SSRF) vulnerability via the ProxyServlet component.

SOURCES

Other Synacor flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.