Vulnerability record

CVE-2019-9621

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

HighExploitation confirmedCISA KEV

What should I do?

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Zimbra Collaboration Suite (ZCS), fix it now.

CISA 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.

US federal civilian agencies must remediate by Jul 28, 2025.

Patch status

No official fix confirmed yet

Until a fix ships, follow the vendor's mitigations and CISA's required action, limit exposure of affected systems, and watch this record for a patch.

Description

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.

Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.

Affected products

Products affected by this vulnerability, with versions and the source of each entry
Product	Vendor	Affected versions	Fixed in	Source
Zimbra Collaboration Suite	Synacor	< 8.6.0; >= 8.7.0, < 8.7.11; >= 8.8.0, < 8.8.9; 8.6.0; 8.7.11; 8.8.9	8.6.0; 8.7.11; 8.8.9	NVD
Zimbra Collaboration Suite (ZCS)	Synacor	—	—	KEV

Sources: NVD = NIST National Vulnerability Database; KEV = CISA Known Exploited Vulnerabilities catalog.

Intelligence timeline

Developments from the last 30 days, newest first.

CVSS scoredUpdateKEVSep 30, 2026
CVE-2019-9621 scored CVSS 7.5: Synacor Zimbra Collaboration Suite (ZCS), Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability
CISA lists this as exploited in the wild. Unpatched Zimbra Collaboration Suite (ZCS) systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database

1 earlier event is available with a subscription. See plans.

Coverage

We have not published a story about this vulnerability yet.

References

wiki.zimbra.com https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
wiki.zimbra.com https://wiki.zimbra.com/wiki/Security_Center
nvd.nist.gov https://nvd.nist.gov/vuln/detail/CVE-2019-9621
packetstormsecurity.com http://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.ht…
packetstormsecurity.com http://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html
rapid7.com http://www.rapid7.com/db/modules/exploit/linux/http/zimbra_xxe_rce
blog.tint0.com https://blog.tint0.com/2019/03/a-saga-of-code-executions-on-zimbra.html
blog.zimbra.com https://blog.zimbra.com/2019/03/9826/
bugzilla.zimbra.com https://bugzilla.zimbra.com/show_bug.cgi?id=109127
exploit-db.com https://www.exploit-db.com/exploits/46693/
cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-9621