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Vulnerabilities

Vulnerability · CVE-2019-9621

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

Published Apr 30, 2019 · catalog updated Jun 16, 2026 · Synacor Zimbra Collaboration Suite (ZCS)

Patch now

CVE-2019-9621 is in the CISA known-exploited catalog, due Jul 28, 2025. Confirm Synacor Zimbra Collaboration Suite (ZCS) against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High7.5
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
81.04%
Remediation
Remediation guidance
Affected products
cpe synacor/zimbra collaboration suite · vendor Synacor Zimbra Collaboration Suite (ZCS)

Zimbra Collaboration Suite before 8.6 patch 13, 8.7.x before 8.7.11 patch 10, and 8.8.x before 8.8.10 patch 7 or 8.8.x before 8.8.11 patch 3 allows SSRF via the ProxyServlet component.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe synacor/zimbra collaboration suite8.6.0
  • vendor Synacor Zimbra Collaboration Suite (ZCS)version unspecified

How to fix CVE-2019-9621

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2019-9621 is in the CISA known-exploited catalog, due Jul 28, 2025. Confirm Synacor Zimbra Collaboration Suite (ZCS) against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with synacor/zimbra collaboration suite 8.6.0. 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 should an analyst verify?

CWE-807; CWE-918: Server-Side Request Forgery (SSRF). EPSS 81.04%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 30, 2019 · Catalog

    Detected

    Zimbra Collaboration Suite before 8.6 patch 13, 8.7.x before 8.7.11 patch 10, and 8.8.x before 8.8.10 patch 7 or 8.8.x before 8.8.11 patch 3 allows SSRF via the ProxyServlet component.

  2. Jul 7, 2025 · CISA KEV

    Known exploited

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

  3. Jul 28, 2025 · CISA KEV

    Remediation 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.

  4. Jun 16, 2026 · Catalog

    Updated

    Zimbra Collaboration Suite before 8.6 patch 13, 8.7.x before 8.7.11 patch 10, and 8.8.x before 8.8.10 patch 7 or 8.8.x before 8.8.11 patch 3 allows SSRF via the ProxyServlet component.

Sources

  • CISA KEVConfirmed exploitationCVE-2019-9621

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

    cisa.gov
  • CVE.orgVulnerability recordCVE-2019-9621

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2019-9621

    30-day exploitation probability 81.0%

    first.org
  • Exploit DatabasePublic exploit reference46693

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Exploit DatabasePublic exploit reference46967

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Metasploit ModulesPublic exploit moduleexploit_linux/http/zimbra_xxe_rce

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2019-9621

    Zimbra Collaboration Suite before 8.6 patch 13, 8.7.x before 8.7.11 patch 10, and 8.8.x before 8.8.10 patch 7 or 8.8.x before 8.8.11 patch 3 allows SSRF via the ProxyServlet component.

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • VulnCheck KEVConfirmed exploitationCVE-2019-9621

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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.