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

known ransomware use

Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability

Added to KEV
2022-04-19
Federal due date
2022-05-10
Vendor
Synacor
Product
Zimbra Collaboration Suite (ZCS)
EPSS
97.8th percentile (score 0.253, as of 2026-09-16)
NVD CVSS v3.1
6.1 (MEDIUM)
Ransomware use
Known
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2018-6882

CISA short description

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that might allow remote attackers to inject arbitrary web script or HTML.

Required action

Apply updates per vendor instructions.

NVD description

Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Suite (ZCS) before 8.7 Patch 1 and 8.8.x before 8.8.7 might allow remote attackers to inject arbitrary web script or HTML via a Content-Location header in an email attachment.

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.