CVE-2023-34192
Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability
Synacor Zimbra Collaboration Suite (ZCS)
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 25 February 2025. US federal agencies were required to remediate it by 18 March 2025.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 77.3%, which is higher than 99.5% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Frequently asked questions
Is CVE-2023-34192 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2023-34192.
What does CVE-2023-34192 affect?
CVE-2023-34192 affects Synacor Zimbra Collaboration Suite (ZCS). 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.
How severe is CVE-2023-34192?
CVE-2023-34192 is rated CRITICAL with a CVSS base score of 9. EPSS puts the probability of exploitation in the next 30 days at 77.3%, higher than 99.5% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 18 March 2025.
How should organisations respond to CVE-2023-34192?
Apply the vendor patch for Synacor Zimbra Collaboration Suite (ZCS) as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.