medium5.4
CVE-2026-0999
Mattermost fails to properly validate login method restrictions
Impact
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
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost/server/v8 | < 8.0.0-20251212052346-61651b0df7ea | 8.0.0-20251212052346-61651b0df7ea |
| go | github.com/mattermost/mattermost-server | >= 11.1.0, < 11.1.3 | none recorded |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mattermost | Mattermost Server | from 10.11.0 before 10.11.10 from 11.1.0 before 11.1.3 from 11.2.0 before 11.2.2 |