PT-2020-8425 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2025-12-15 · CVE-2017-18879

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 4.3.0 Mattermost Server version 4.2.1 Mattermost Server version 4.1.2

Description: An issue was discovered in Mattermost Server. XSS could occur via the author link field of a Slack attachment.

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. As a temporary workaround, consider restricting the use of the author link field in Slack attachments until a patch is available.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2017-18879

GHSA-498J-WXWW-J897

GO-2025-4189

SUSE-SU-2025:4395-1

Affected Products

Mattermost Server

References · 46

• https://nvd.nist.gov/vuln/detail/CVE-2017-18879 · Security Note
• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2017-18879 · Vendor Advisory
• https://osv.dev/vulnerability/GO-2025-4189 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2025:4395-1 · Vendor Advisory
• https://suse.com/security/cve/CVE-2017-18884 · Note
• https://suse.com/security/cve/CVE-2017-18871 · Note
• https://suse.com/security/cve/CVE-2025-12756 · Note
• https://suse.com/security/cve/CVE-2025-65025 · Note
• https://suse.com/security/cve/CVE-2025-13870 · Note
• https://suse.com/security/cve/CVE-2025-66564 · Note
• https://suse.com/security/cve/CVE-2025-61727 · Note
• https://suse.com/security/cve/CVE-2025-64443 · Note
• https://suse.com/security/cve/CVE-2025-13353 · Note
• https://suse.com/security/cve/CVE-2025-64761 · Note