Signal is active with 2 mentions in latest observed window
Recommended action window: Monitor and triage in normal cycle
NVD 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
Priority
LOW
Exploitation
NONE
PoC
NONE
Patch
NONE
Momentum
NONE
If you run products in this scope, you should treat this CVE as relevant to your environment.
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 an authenticated user to byp… https://www.cve.org/CVERecord?id=CVE-2026-0999
Post summary
CVE-2026-0999 impacts Mattermost up to specific versions, permitting authenticated users to bypass login restrictions; no exploit, patch, or active exploitation details are included.
CVE-2026-0999 Mattermost SSO Bypass Vulnerability in Versions 10.11.x, 11.1.x, a... https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-0999 Vulnerability Alert Subscriptions: https://alerts.vulmon.com/?utm_source=twitter&utm_medium=social&utm_campaign=2102281&utm_content=1
Post summary
The post announces the disclosure of a Mattermost SSO bypass vulnerability (CVE‑2026‑0999) affecting specific versions and provides links to additional details.
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| Part | Vendor | Product | Version | Target SW | Target HW |
|---|---|---|---|---|---|
| App | mattermost | mattermost_server | - | - | - |