CVE-2023-37580
Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability
Synacor Zimbra Collaboration Suite (ZCS)
Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 27 July 2023. US federal agencies were required to remediate it by 17 August 2023.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 49.1%, which is higher than 98.9% 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:N/UI:R/S:C/C:L/I:L/A:N
Frequently asked questions
Is CVE-2023-37580 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2023-37580.
What does CVE-2023-37580 affect?
CVE-2023-37580 affects Synacor Zimbra Collaboration Suite (ZCS). Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
How severe is CVE-2023-37580?
CVE-2023-37580 is rated MEDIUM with a CVSS base score of 6.1. EPSS puts the probability of exploitation in the next 30 days at 49.1%, higher than 98.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 17 August 2023.
How should organisations respond to CVE-2023-37580?
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.