PT-2020-8437 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-01-17 · CVE-2017-18891

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 in Mattermost Server allows phishing because an error page can contain a link.

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

Fix

Open Redirect

Weakness Enumeration

CWE-601

Related Identifiers

CVE-2017-18891

GHSA-VRH2-RPRG-RGC6

GO-2026-4298

SUSE-SU-2026:0142-1

Affected Products

Mattermost Server

References · 44

• https://nvd.nist.gov/vuln/detail/CVE-2017-18891 · Security Note
• https://osv.dev/vulnerability/GHSA-vrh2-rprg-rgc6 · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-4298 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2017-18891 · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/pull/7378 · Note
• https://t.me/cibsecurity/12916 · Telegram Post
• 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-2025-68954 · Note
• https://suse.com/security/cve/CVE-2026-22703 · Note
• https://suse.com/security/cve/CVE-2017-18905 · Note