Synacor · Zimbra Collaboration Suite (ZCS)
CVE-2019-9670
Synacor Zimbra Collaboration Suite (ZCS) Improper Restriction of XML External Entity Reference
What it is
mailboxd component in Synacor Zimbra Collaboration Suite 8.7.x before 8.7.11p10 has an XML External Entity injection (XXE) vulnerability, as demonstrated by Autodiscover/Autodiscover.xml.
CISA: Synacor Zimbra Collaboration Suite (ZCS) contains an improper restriction of XML external entity (XXE) vulnerability in the mailboxd component.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: July 10, 2022
- Added to the CISA list
- January 10, 2022
- Published
- May 29, 2019
- Severity
- Critical 9.8 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- >99.9% in the top 0.1% of all known vulnerabilities
- Weakness
- CWE-611
- More details
- NVD · CVE.org · CISA
All references (6)
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- https://bugzilla.zimbra.com/show_bug.cgi?id=109129
- 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://isc.sans.edu/forums/diary/CVE20199670+Zimbra+Collaboration+Suite+XXE+vulnerability/27570/
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% |
| Jul 7, 2025 | Server-Side Request Forgery (SSRF) | Zimbra Collaboration Suite (ZCS) | High 7.5 | 81% |
| 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% |
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.