---
id: "CVE-2019-9621"
kind: "vulnerability"
aliases: ["CVE-2019-9621"]
title: "synacor zimbra collaboration suite: 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\u2026"
severity: "high"
cvss: 7.5
epss: null
exploited: true
status: "open"
category: "other"
products: [{"name": "Synacor Zimbra Collaboration Suite (ZCS)", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": ["8.6.0"], "affected": "< 8.6.0", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": ["8.7.11"], "affected": ">= 8.7.0, < 8.7.11", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": ["8.8.9"], "affected": ">= 8.8.0, < 8.8.9", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.6.0", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.7.11", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.8.9", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.8.10", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.8.11", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["email", "exploited", "other", "self-hosted", "zimbra"]
not_affected_if: ["unknown"]
published_at: "2019-04-30T18:29:08+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:05+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-9621", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2019-9621", "first_seen_at": "2026-10-23T22:29:05+00:00"}]
---

# synacor zimbra collaboration suite: 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…

Zimbra Collaboration Suite has a server-side request forgery flaw in its ProxyServlet component. An attacker can make the mail server send requests to internal hosts or other targets on its behalf.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Synacor Zimbra Collaboration Suite (ZCS) affected ? fixed ?
- vendor:synacor zimbra collaboration suite affected < 8.6.0 fixed 8.6.0
- vendor:synacor zimbra collaboration suite affected >= 8.7.0, < 8.7.11 fixed 8.7.11
- vendor:synacor zimbra collaboration suite affected >= 8.8.0, < 8.8.9 fixed 8.8.9
- vendor:synacor zimbra collaboration suite affected = 8.6.0 fixed ?
- vendor:synacor zimbra collaboration suite affected = 8.7.11 fixed ?
- vendor:synacor zimbra collaboration suite affected = 8.8.9 fixed ?
- vendor:synacor zimbra collaboration suite affected = 8.8.10 fixed ?
- vendor:synacor zimbra collaboration suite affected = 8.8.11 fixed ?

## Fix

Apply the mitigations from the vendor (Synacor/Zimbra) per CISA guidance, or discontinue use of the product if mitigations are unavailable.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2019-9621
- 2026-10-23T22:29:05+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2019-9621

## From the sources

Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery (SSRF) vulnerability via the ProxyServlet component.

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.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_