Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability (CVE-2019-9621)
Severity: high · Patch status: unknown · Since 2025-07-07 · CVE-2019-9621
Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery (SSRF) vulnerability via the ProxyServlet component. CISA added CVE-2019-9621 to its Known Exploited Vulnerabilities catalog on Jul 7, 2025, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Jul 28, 2025 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch