PT-2020-8419 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-03-03 · CVE-2017-18873

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 4.3.0 Mattermost Server version 4.2.1 Mattermost Server version 4.1.2

Description: The issue allows attackers to cause a denial of service, resulting in channel invisibility, via a misformatted post.

Recommendations: For versions prior to 4.3.0, update to version 4.3.0 or later. For version 4.2.1, update to version 4.3.0 or later. For version 4.1.2, update to version 4.3.0 or later.

Fix

DoS

RCE

Weakness Enumeration

CWE-20

Related Identifiers

CVE-2017-18873

GHSA-X6MW-HF2J-VQPC

GO-2026-4282

SUSE-SU-2026:0757-1

Affected Products

Mattermost Server

References · 118

• https://osv.dev/vulnerability/GHSA-x6mw-hf2j-vqpc · Vendor Advisory
• https://osv.dev/vulnerability/GO-2026-4282 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0757-1 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2017-18873 · Security Note
• https://osv.dev/vulnerability/CVE-2017-18873 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/commit/ee57a5829ab162859e0e355dac6cfe6ca1a8f379 · Note
• https://github.com/mattermost/mattermost/commit/b3e4b0ac91682093276a653f7ccd5774aaa9cd06 · Note
• https://github.com/mattermost/mattermost/commit/9adaf53e110e0e806b21903111aacb93129668cb · Note
• https://suse.com/security/cve/CVE-2025-64111 · Note
• https://suse.com/security/cve/CVE-2026-0998 · Note
• https://suse.com/security/cve/CVE-2026-22892 · Note
• https://suse.com/security/cve/CVE-2026-24122 · Note
• https://suse.com/security/cve/CVE-2026-21434 · Note