CVE-2019-9621 — Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vuln

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2025-07-07. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-04-30T17:40:53.000Z
• Last modified: 2025-10-21T23:45:38.514Z
• Added to CISA KEV: 2025-07-07
• BOD 22-01 due: 2025-07-28

09References

• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Security_Center
• bugzilla.zimbra.com — https://bugzilla.zimbra.com/show_bug.cgi?id=109127
• www.rapid7.com — http://www.rapid7.com/db/modules/exploit/linux/http/zimbra_xxe_rce
• packetstormsecurity.com — http://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Se…
• www.exploit-db.com — https://www.exploit-db.com/exploits/46693/
• blog.zimbra.com — https://blog.zimbra.com/2019/03/9826/
• blog.tint0.com — https://blog.tint0.com/2019/03/a-saga-of-code-executions-on-zimbra.html
• packetstormsecurity.com — http://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Req…