PT-2020-8450 · Mattermost · Mattermost Server

Published 2020-06-19 · Updated 2026-01-17 · CVE-2017-18904

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 4.0.0 Mattermost Server version 3.10.2 and earlier Mattermost Server version 3.9.2 and earlier

Description: An issue allows XSS via an uploaded file.

Recommendations: For versions prior to 4.0.0, update to version 4.0.0 or later. For version 3.10.2 and earlier, update to version 3.10.3 or later. For version 3.9.2 and earlier, update to version 3.9.3 or later.

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2017-18904

GHSA-8PFF-P3GX-W4JF

GO-2026-4302

SUSE-SU-2026:0142-1

Affected Products

Mattermost Server

References · 44

• https://nvd.nist.gov/vuln/detail/CVE-2017-18904 · Security Note
• https://osv.dev/vulnerability/GO-2026-4302 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-8pff-p3gx-w4jf · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2017-18904 · Vendor Advisory
• https://mattermost.com/security-updates · Vendor Advisory
• https://github.com/mattermost/mattermost · Note
• https://github.com/mattermost/mattermost/commit/bde06a7bc3a03a56da224c1ffcd8bffb0af8071b · Note
• https://github.com/mattermost/mattermost/commit/f06c5bef4d78966c60b153bbec6eea4ec0be9e68 · Note
• https://github.com/mattermost/mattermost/commit/6a2754376c8c8270be5e11e3fdab589659d0cc8d · 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