CVE-2026-0999
published 2026-02-16CVE-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 an authenticated…
PriorityP423medium4.3CVSS 3.1
AVNACLPRLUINSUCNILAN
EPSS
0.17%
6.9th percentile
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
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost-server | >= 0 < 5.3.2-0.20251212052346-61651b0df7ea | 5.3.2-0.20251212052346-61651b0df7ea |
| github.com | mattermost_mattermost-server | >= 10.11.0 | — |
| github.com | mattermost_mattermost-server | >= 10.11.0+incompatible | — |
| github.com | mattermost_mattermost-server | >= 11.1.0 | — |
| github.com | mattermost_mattermost-server | >= 11.1.0+incompatible | — |
| github.com | mattermost_mattermost-server | >= 11.2.0 | — |
| github.com | mattermost_mattermost-server | >= 11.2.0+incompatible | — |
| github.com | mattermost_mattermost_server_v8 | >= 0 < 8.0.0-20251212052346-61651b0df7ea | 8.0.0-20251212052346-61651b0df7ea |
| mattermost | mattermost | 10.11.0 – 10.11.9 | — |
| mattermost | mattermost | 11.1.0 – 11.1.2 | — |
| mattermost | mattermost | 11.2.0 – 11.2.1 | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.10 | 10.11.10 |
| mattermost | mattermost_server | >= 11.1.0 < 11.1.3 | 11.1.3 |
| mattermost | mattermost_server | >= 11.2.0 < 11.2.2 | 11.2.2 |
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OSV
Mattermost fails to properly validate login method restrictions in github.com/mattermost/mattermost-server
osv·2026-02-23
CVE-2026-0999 Mattermost fails to properly validate login method restrictions in github.com/mattermost/mattermost-server
Mattermost fails to properly validate login method restrictions in github.com/mattermost/mattermost-server
Mattermost fails to properly validate login method restrictions in github.com/mattermost/mattermost-server.
NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.
(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)
The additional affected modules and versions are: github.com/mattermost/mattermost-server/v5 before v5.3.2-0.20251212052346-61651b0df7ea.
GHSA
Mattermost fails to properly validate login method restrictions
ghsa·2026-02-16
CVE-2026-0999 [MEDIUM] CWE-303 Mattermost fails to properly validate login method restrictions
Mattermost fails to properly validate login method restrictions
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
OSV
Mattermost fails to properly validate login method restrictions
osv·2026-02-16
CVE-2026-0999 [MEDIUM] Mattermost fails to properly validate login method restrictions
Mattermost fails to properly validate login method restrictions
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
No detection rules found.
No public exploits indexed.
2026-02-16
Published