Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 25.4%; technical severity is CVSS 6.1.
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.
Who should care
- Teams operating Zimbra Collaboration Suite, Zimbra Collaboration Suite (ZCS)
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Zimbra Collaboration Suite, Zimbra Collaboration Suite (ZCS) is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Vendor advisory from wiki.zimbra.com
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Verification noteAutomated link verification has not completed for this guidance yet.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CWE
- CWE-79
- Affected versions
- Synacor Zimbra Collaboration Suite (End Excluding 8.7.0 | Version 8.7.0 | Version 8.8.0 | Version 8.8.1); Synacor Zimbra Collaboration Suite (ZCS)
- Fixed versions
- Synacor Zimbra Collaboration Suite (Fixed from 8.7.0)
- Published
- 27 March 2018
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 25.4%
- Signal calculated at 74