---
id: "CVE-2023-37580"
kind: "vulnerability"
aliases: ["CVE-2023-37580"]
title: "synacor zimbra collaboration suite: Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client"
severity: "high"
cvss: 6.1
epss: null
exploited: true
status: "open"
category: "package"
products: [{"name": "Synacor Zimbra Collaboration Suite (ZCS)", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": ["8.8.15"], "affected": ">= 8.8.0, < 8.8.15", "ecosystem": "vendor"}, {"name": "synacor zimbra collaboration suite", "fixed": [], "affected": "= 8.8.15", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["email", "exploited", "package", "self-hosted", "zimbra"]
not_affected_if: ["managed-hosting"]
published_at: "2023-07-27T00:00:00+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:04+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-37580", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-37580", "first_seen_at": "2026-10-23T22:29:04+00:00"}]
---

# synacor zimbra collaboration suite: Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client

Synacor Zimbra Collaboration Suite (ZCS) has a cross-site scripting flaw that can affect the confidentiality and integrity of data. CISA lists it as exploited in the wild, so attackers are already using it.

_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 >= 8.8.0, < 8.8.15 fixed 8.8.15
- vendor:synacor zimbra collaboration suite affected = 8.8.15 fixed ?

## Fix

Apply the mitigations per vendor instructions, or discontinue use of the product if mitigations are unavailable (per CISA required action).

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-37580
- 2026-10-23T22:29:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-37580

## From the sources

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability impacting the confidentiality and integrity of data.

CISA required action: Apply mitigations per vendor instructions 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_