CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- Apply updates per vendor instructions.
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.
Affected products
synacor: zimbra collaboration suite
References10
- wiki.zimbra.com/wiki/Zimbra_Security_Advisories Vendor Advisory
- wiki.zimbra.com/wiki/Zimbra_Security_Advisories Vendor Advisory
- www.securify.nl/advisory/SFY20180101/cross-site-scripting-vulne… ExploitThird Party Advisory
- www.securify.nl/advisory/SFY20180101/cross-site-scripting-vulne… ExploitThird Party Advisory
- seclists.org/fulldisclosure/2018/Mar/52 Mailing ListThird Party Advisory
- www.securityfocus.com/archive/1/541891/100/0/threaded Broken LinkThird Party AdvisoryVDB Entry
- bugzilla.zimbra.com/show_bug.cgi?id=108786 Broken LinkIssue TrackingPermissions Required
- wiki.zimbra.com/wiki/Zimbra_Releases/8.8.7 Permissions Required
- seclists.org/fulldisclosure/2018/Mar/52 Mailing ListThird Party Advisory
- www.securityfocus.com/archive/1/541891/100/0/threaded Broken LinkThird Party AdvisoryVDB Entry
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 30% percentile: 98 · as of 10 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.