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…

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.

1. 2019-03-13 First public exploit (Metasploit exploit/linux/http/zimbra_xxe_rce)
2. 2019-04-30 Published
3. 2025-07-07 Added to CISA KEV
4. 2025-07-17 CISA SSVC: exploitation active
5. 2025-07-28 CISA patch deadline

Added

16 mo ago (2025-07-07)

Patch by

2025-07-28 (15 mo ago)

Ransomware

Not known

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.

Vendor, product

Synacor, Zimbra Collaboration Suite (ZCS)

CISA name

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

Exploitation

Active, exploited in the wild

Automatable

yes

Technical impact

partial

Assessed

15 mo ago (2025-07-17)

81.04% chance of exploitation in the next 30 days, higher than 99.6% of all scored CVEs (FIRST EPSS, 2026-11-08).

• Metasploit exploit/linux/http/zimbra_xxe_rce Zimbra Collaboration Autodiscover Servlet XXE and ProxyServlet SSRF metasploit exploit, excellent rank, 2019-03-13
• EDB-46967 Zimbra < 8.8.11 - XML External Entity Injection / Server-Side Request Forgery webapps, 2019-06-05
• EDB-46693 Zimbra Collaboration - Autodiscover Servlet XXE and ProxyServlet SSRF (Metasploit) remote, 2019-04-12
• Nuclei template Zimbra Collaboration Suite - SSRF nuclei detection template
• rapid7.com http://www.rapid7.com/db/modules/exploit/linux/http/zimbra_xxe_rce referenced PoC, tagged "exploit" by a source, unverified
• packetstormsecurity.com http://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.html referenced PoC, tagged "exploit" by a source, unverified
• packetstormsecurity.com http://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html referenced PoC, tagged "exploit" by a source, unverified

Weakness

• CWE-918 Server-Side Request Forgery

• exploit-db.com /exploits/46693/

  exploit, third-party-advisory, vdb-entry

• rapid7.com /db/modules/exploit/linux/http/zimbra_xxe_rce

  exploit, third-party-advisory

• packetstormsecurity.com /files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.html

  exploit, third-party-advisory, vdb-entry

• packetstormsecurity.com /files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html

  exploit, third-party-advisory, vdb-entry

• wiki.zimbra.com /wiki/Zimbra_Security_Advisories

  vendor-advisory

• wiki.zimbra.com /wiki/Security_Center

  release-notes, vendor-advisory

• blog.zimbra.com /2019/03/9826/

  vendor-advisory

• bugzilla.zimbra.com /show_bug.cgi?id=109127

  issue-tracking

• blog.tint0.com /2019/03/a-saga-of-code-executions-on-zimbra.html

  third-party-advisory

• cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-9621

  government-resource, us-government-resource

• CVE List CVE-2019-9621
• NVD CVE-2019-9621

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.