CVEs / CVE-2023-34192

CVE-2023-34192: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability

Known exploited in the CISA KEV catalog since 25 Feb 2025
critical 9 CVSS 3.1 (NVD)
EPSS 77.2% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
Last changed at its sources 28 Oct 2026

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Summary

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting (XSS) vulnerability that allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.
CISA, Known Exploited Vulnerabilities catalog

Description

Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.
The CVE record, via NVD · published 6 Jul 2023 · NVD status: Analyzed

Affected and fixed versions

As stated by the CVE record (from the CNA)
Product	Affected	Fixed in
n/a n/a	n/a	—

Exploitation

In CISA KEV since	25 Feb 2025
Due date for US federal agencies	18 Mar 2025
Used in ransomware campaigns	Unknown
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.

Severity

CVSS 3.1	9 critical `CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H` Scored by NVD
Weakness	CWE-79

References

CVE-2023-34192 on NVD
CVE-2023-34192 in the CISA KEV catalog
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories (cited by CISA)
CVE-2023-34192 on OSV
https://wiki.zimbra.com/wiki/Security_Center Release Notes, Vendor Advisory
https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy Not Applicable
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-34192 US Government Resource

Sources

Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.

This product uses data from the NVD API but is not endorsed or certified by the NVD.