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HIGH · CVSS 8.8 CISA Known Exploited Vulnerability

CVE-2025-68645

Synacor Zimbra Collaboration Suite (ZCS) PHP Remote File Inclusion Vulnerability

Synacor Zimbra Collaboration Suite (ZCS)

A Local File Inclusion (LFI) vulnerability exists in the Webmail Classic UI of Zimbra Collaboration (ZCS) 10.0 and 10.1 because of improper handling of user-supplied request parameters in the RestFilter servlet. An unauthenticated remote attacker can craft requests to the /h/rest endpoint to influence internal request dispatching, allowing inclusion of arbitrary files from the WebRoot directory.

CVSS
8.8
HIGH
EPSS
48.9%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
22 Dec 2025
CWE-98

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 22 January 2026. US federal agencies were required to remediate it by 12 February 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 48.9%, 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:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2025-68645 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2025-68645.

What does CVE-2025-68645 affect?

CVE-2025-68645 affects Synacor Zimbra Collaboration Suite (ZCS). A Local File Inclusion (LFI) vulnerability exists in the Webmail Classic UI of Zimbra Collaboration (ZCS) 10.0 and 10.1 because of improper handling of user-supplied request parameters in the RestFilter servlet. An unauthenticated remote attacker can craft requests to the /h/rest endpoint to influence internal request dispatching, allowing inclusion of arbitrary files from the WebRoot directory.

How severe is CVE-2025-68645?

CVE-2025-68645 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 48.9%, higher than 98.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 12 February 2026.

How should organisations respond to CVE-2025-68645?

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.