Known Exploited Vulnerability

CVE-2019-9621

Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability

Past federal due date 15 public exploits Added 07 Jul 2025 Due 28 Jul 2025 · 370 days ago
VendorSynacor
ProductZimbra Collaboration Suite (ZCS)
WeaknessCWE-918, CWE-807
RansomwareNone confirmed

What the flaw is

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

Description as published by CISA. We have not independently reproduced it.

What CISA requires

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

15 public repositories referencing this CVE have been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

Showing 8 of 15. Full list in the trickest/cve dataset.

Vendor advisories

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Source: CISA KEV catalog · last verified July 31, 2026. Rebuilt automatically twice a day.