PT-2020-8439 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-01-17 · CVE-2017-18893

Positive Technologies (AI Summary)

CVSS v3.1

6.1

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions: Mattermost Server versions prior to 4.2.0 Mattermost Server version 4.1.1 Mattermost Server version 4.0.5

Description: An issue was discovered that allows XSS through display names.

Recommendations: For versions prior to 4.2.0, update to version 4.2.0 or later to resolve the issue. For version 4.1.1, update to version 4.2.0 or later to resolve the issue. For version 4.0.5, update to version 4.2.0 or later to resolve the issue.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2017-18893

GHSA-887V-XH2X-47CM

GO-2026-4296

SUSE-SU-2026:0142-1

Affected Products

Mattermost Server

References · 45

• https://nvd.nist.gov/vuln/detail/CVE-2017-18893 · Security Note
• https://osv.dev/vulnerability/GHSA-887v-xh2x-47cm · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2017-18893 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-4296 · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/commit/2a4d88d07c5815deac103e109550d25338507151 · Note
• https://github.com/mattermost/mattermost/commit/670bfbf62686ebe9f2ab332733d851a62b6950b0 · Note
• https://github.com/mattermost/mattermost/commit/d0b42b9e527e93a61fd06a9b9106fc97067807e4 · Note
• https://suse.com/security/cve/CVE-2026-22688 · Note
• https://suse.com/security/cve/CVE-2026-21859 · Note
• https://suse.com/support/update/announcement/2026/suse-su-20260142-1 · Note
• https://suse.com/security/cve/CVE-2026-22703 · Note
• https://suse.com/security/cve/CVE-2025-68954 · Note