Exploited CVEs / Synacor / CVE-2019-9621
CVE-2019-9621
Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2025-07-28 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Zimbra Security Center, linked below.
Actively exploited Synacor Zimbra Collaboration Suite (ZCS) vulnerability, High severity, CVSS 7.5. Added to the CISA KEV catalog 2025-07-07.
Risk summary
Updated July 30, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2019-9621
A 2019 SSRF flaw in Zimbra Collaboration Suite's ProxyServlet did not reach the CISA KEV catalog until July 2025, a six-year gap that shows attackers still profit from ancient Zimbra bugs. SSRF on a mail server lets attackers pivot to internal services and metadata endpoints the server can reach, and Zimbra has been a repeat target of espionage-driven campaigns. The 81 percent EPSS score confirms active interest.
Do this: Upgrade Zimbra to a current release and audit the server for webshells and unexpected outbound connections.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2019-9621
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2019-9621
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2025-07-28 (past due).
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Official fix for CVE-2019-9621
The authoritative fix and affected-version list are published by the vendor. Find the Zimbra Collaboration Suite (ZCS) advisory on Zimbra Security Center.
Common questions about CVE-2019-9621
Is CVE-2019-9621 actively exploited?
Yes. CVE-2019-9621 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2025-07-07, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 81%.
What is the CISA deadline and required action for CVE-2019-9621?
CISA set the federal (BOD 22-01) remediation due date at 2025-07-28, which has passed; treat any unremediated system as overdue. The verbatim 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.
What fixes CVE-2019-9621?
The authoritative fix is in the vendor advisory: see Zimbra Security Center for the patched Zimbra Collaboration Suite (ZCS) versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2019-9621?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2019-9621's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
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