Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

known ransomware use

Synacor Zimbra Collaborate Suite (ZCS) Cross-Site Scripting Vulnerability

Added to KEV
2022-02-25
Federal due date
2022-03-11
Vendor
Synacor
Product
Zimbra Collaborate Suite (ZCS)
EPSS
98.2th percentile (score 0.309, as of 2026-09-16)
NVD CVSS v3.1
6.1 (MEDIUM)
Ransomware use
Known
ATT&CK
T1059.007 , T1185 , T1204.001 · signal rollup
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2022-24682

CISA short description

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting (XSS) vulnerability in the Calendar feature that allows an attacker to execute arbitrary code.

Required action

Apply updates per vendor instructions.

NVD description

An issue was discovered in the Calendar feature in Zimbra Collaboration Suite 8.8.x before 8.8.15 patch 30 (update 1), as exploited in the wild starting in December 2021. An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.