GitHub Advisoryadvisory · Go

GHSA-3c9r-7f29-qp32 Mattermost fails to properly validate login method restrictions

MEDIUM Published 2026-02-16 Modified 2026-02-19 Official page ↗
Aliases
CVE-2026-0999
Ecosystem
Go
Packages
github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Weaknesses
CWE-303
Reviewed
2026-02-19

Affected packages

• Go github.com/mattermost/mattermost/server/v8: < 8.0.0-20251212052346-61651b0df7ea → fixed in 8.0.0-20251212052346-61651b0df7ea • Go github.com/mattermost/mattermost-server: < 11.1.3 (no fix yet) • Go github.com/mattermost/mattermost-server: < 10.11.10 (no fix yet) • Go github.com/mattermost/mattermost-server: < 11.2.2 (no fix yet) • Go github.com/mattermost/mattermost-server: < 5.3.2-0.20251212052346-61651b0df7ea → fixed in 5.3.2-0.20251212052346-61651b0df7ea

Description

Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows an authenticated user to bypass SSO-only login requirements via userID-based authentication. Mattermost Advisory ID: MMSA-2025-00548

Related

Alias · CVE (1)

  • CVE-2026-0999 Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate login method restrictions which allows… vulnerability

Weakness · CWE (1)

  • CWE-303 Incorrect Implementation of Authentication Algorithm weakness

References