PT-2020-8455 · Mattermost · Mattermost Server

CVE-2017-18909

Published

2020-06-19

Updated

2026-07-30

CVSS v3.1

7.5

High

Vector

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

Name of the Vulnerable Software and Affected Versions: Mattermost Server versions prior to 3.9.0

Description: An issue was discovered when SAML is used, where encryption and signature verification are not mandatory.

Recommendations: For versions prior to 3.9.0, update to version 3.9.0 or later to resolve the issue.

Fix

Improper Verification of Cryptographic Signature

Missing Encryption of Sensitive Data

Improper Certificate Validation

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CVE-2017-18909

GHSA-R6J5-FQX9-7QV9

GO-2026-4478

OPENSUSE-SU-2026:21483-1

SUSE-SU-2026:0757-1

Mattermost Server