CVE-2017-18921

Name: CVE-2017-18921
Creator: NVD / NIST
Published: 2020-06-19T20:15:12.773+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.69%

Last modified Jun 17, 2026

CVE-2017-18921 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. An issue was discovered in Mattermost Server before 3.6.0 and 3.5.2. XSS can occur via a link on an error page.. EPSS estimates a 0.69% chance of exploitation in the next 30 days.

Description

An issue was discovered in Mattermost Server before 3.6.0 and 3.5.2. XSS can occur via a link on an error page.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.69%

47.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Mattermost	Mattermost Server	< 3.5.2

References

https://mattermost.com/security-updates/Vendor Advisory
https://mattermost.com/security-updates/Vendor Advisory

Timeline

Published: Jun 19, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-18921?

An issue was discovered in Mattermost Server before 3.6.0 and 3.5.2. XSS can occur via a link on an error page.

How severe is CVE-2017-18921?

CVE-2017-18921 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.69% probability of exploitation in the next 30 days.

How do I fix CVE-2017-18921?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2017-18921?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST