What is CVE-2018-6882?

CVE-2018-6882 is a medium-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-03-27.

How severe is CVE-2018-6882?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2018-6882 known to be exploited?

Yes. CVE-2018-6882 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-04-19), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.

XSS in Synacor Zimbra Collaboration Suite

CVE-2018-6882

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-03-27 · last modified 2026-10-01.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.298 (98.2th percentile), scored 2026-10-19.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 98.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.253 · newest: 0.298 · change: +0.045

Affected products

Synacor Zimbra Collaboration Suite — versions 8.7.0, 8.8.0, 8.8.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-04-19. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-10.

Required action: Apply updates per vendor instructions.

Known ransomware campaign use: yes.

Public proof-of-concept exploits

References

seclists.org/fulldisclosure/2018/Mar/52 (mailing-list, Mailing List, Third Party Advisory)
www.securify.nl/advisory/SFY20180101/cross-site-scripting-vulnerability-in-zimb… (Exploit, Third Party Advisory)
wiki.zimbra.com/wiki/Zimbra_Releases/8.8.7 (Permissions Required)
bugzilla.zimbra.com/show_bug.cgi (Permissions Required, Issue Tracking, Broken Link)
www.securityfocus.com/archive/1/541891/100/0/threaded (mailing-list, VDB Entry, Third Party Advisory, Broken Link)
wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2018-6882?: CVE-2018-6882 is a medium-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-03-27.
How severe is CVE-2018-6882?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2018-6882 known to be exploited?: Yes. CVE-2018-6882 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-04-19), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.