Synacor · Zimbra Collaboration Suite (ZCS)
CVE-2019-9621
Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability
What it is
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.
CISA: Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery (SSRF) vulnerability via the ProxyServlet component.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Deadline for US federal agencies: July 28, 2025
- Added to the CISA list
- July 7, 2025
- Published
- April 30, 2019
- Severity
- High 7.5 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 81% in the top 0.4% of all known vulnerabilities
- Weakness
- CWE-918 CWE-807
- More details
- NVD · CVE.org · CISA
All references (9)
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- https://wiki.zimbra.com/wiki/Security_Center
- https://bugzilla.zimbra.com/show_bug.cgi?id=109127
- http://www.rapid7.com/db/modules/exploit/linux/http/zimbra_xxe_rce
- http://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.h…
- https://www.exploit-db.com/exploits/46693/
- https://blog.zimbra.com/2019/03/9826/
- https://blog.tint0.com/2019/03/a-saga-of-code-executions-on-zimbra.html
- http://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html
More exploited flaws from Synacor
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Aug 21, 2026 | OS Command Injection | Zimbra Collaboration Suite (ZCS) | High 8.9 | 72% |
| Apr 20, 2026 | Cross-site Scripting | Zimbra Collaboration Suite (ZCS) | Medium 6.1 | 1.7% |
| Mar 18, 2026 | Cross-Site Scripting | Zimbra Collaboration Suite (ZCS) | High 7.2 | 20% |
| Oct 7, 2025 | Cross-site Scripting | Zimbra Collaboration Suite (ZCS) | Medium 5.4 | 4.1% |
| May 19, 2025 | Cross-Site Scripting (XSS) | Zimbra Collaboration Suite (ZCS) | Medium 6.1 | 25% |
| Feb 25, 2025 | Cross-Site Scripting (XSS) | Zimbra Collaboration Suite (ZCS) | Critical 9.0 | 77% |
| Oct 3, 2024 | Command Execution | Zimbra Collaboration Suite (ZCS) | Critical 10.0 | 99.9% |
| Jul 27, 2023 | Cross-Site Scripting (XSS) | Zimbra Collaboration Suite (ZCS) | Medium 6.1 | 49% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.