What is CVE-2016-11063?

CVE-2016-11063 is a medium-severity vulnerability in Mattermost Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-06-19.

How severe is CVE-2016-11063?

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

XSS in Mattermost Server

CVE-2016-11063

An issue was discovered in Mattermost Server before 3.5.1. XSS can occur via file preview.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-06-19 · last modified 2026-06-17.

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: 0.007 (50.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

Mattermost Server

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

mattermost.com/security-updates/ (Vendor Advisory)

Frequently asked questions

What is CVE-2016-11063?: CVE-2016-11063 is a medium-severity vulnerability in Mattermost Server, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2020-06-19.
How severe is CVE-2016-11063?: Medium severity. CVSS v3 base score is 6.1 out of 10.