What is CVE-2016-5721?

CVE-2016-5721 is a medium-severity vulnerability in Zimbra Collaboration Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2016-08-29.

How severe is CVE-2016-5721?

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

XSS in Zimbra Collaboration Server

CVE-2016-5721

Multiple cross-site scripting (XSS) vulnerabilities in Zimbra Collaboration before 8.7.0 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2016-08-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.011 (63.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Zimbra Collaboration Server

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.securityfocus.com/bid/92682 (vdb-entry)
wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2016-5721?: CVE-2016-5721 is a medium-severity vulnerability in Zimbra Collaboration Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2016-08-29.
How severe is CVE-2016-5721?: Medium severity. CVSS v3 base score is 6.1 out of 10.