PT-2020-8444 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-01-17 · CVE-2017-18898

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

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

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 crafted posts to potentially cause a web browser to hang.

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

DoS

Improper Resource Release

Weakness Enumeration

CWE-404

Related Identifiers

CVE-2017-18898

GHSA-9589-MQ83-F749

GO-2026-4300

SUSE-SU-2026:0142-1

Affected Products

Mattermost Server

References · 45

• https://osv.dev/vulnerability/GO-2026-4300 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2017-18898 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-9589-mq83-f749 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2017-18898 · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/commit/5c22176c963a7393241872073547f30083efe218 · Note
• https://github.com/mattermost/mattermost/commit/5bf6f06c02c368b9c73a8be2d2d8795b3405b22b · 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://t.me/cibsecurity/12909 · Telegram Post
• https://suse.com/security/cve/CVE-2026-22703 · Note
• https://suse.com/security/cve/CVE-2025-68954 · Note