---
id: "CVE-2018-6882"
kind: "vulnerability"
aliases: ["CVE-2018-6882"]
title: "Synacor Zimbra Collaboration Suite (ZCS): Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability"
severity: "high"
cvss: 6.1
epss: 0.29761
exploited: true
status: "open"
category: "package"
products: [{"name": "Synacor Zimbra Collaboration Suite (ZCS)", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["email", "exploited", "package", "ransomware", "self-hosted", "zimbra"]
not_affected_if: ["managed-hosting"]
published_at: "2018-03-27T16:29:00+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-6882", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2018-6882", "first_seen_at": "2026-10-23T19:13:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-6882", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Synacor Zimbra Collaboration Suite (ZCS): Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability

Zimbra Collaboration Suite has a cross-site scripting flaw that lets a remote attacker inject arbitrary web script or HTML. CISA lists it as actively exploited, and the tags mark it as used in ransomware campaigns.

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

## Affected

- vendor:Synacor Zimbra Collaboration Suite (ZCS) affected ? fixed ?

## Fix

Apply the Zimbra updates per vendor instructions; the sources do not give a fixed version.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-6882
- 2026-10-23T19:13:45+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2018-6882
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2018-6882

## From the sources

Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Suite (ZCS) before 8.7 Patch 1 and 8.8.x before 8.8.7 might allow remote attackers to inject arbitrary web script or HTML via a Content-Location header in an email attachment.

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