ByteOS Network

NVD Vulnerability Details :

CVE-2026-0999

Analyzed

Source-responsibledisclosure@mattermost.com

Published At-16 Feb, 2026 | 10:16

Updated At-18 Feb, 2026 | 20:20

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

Date Added	Due Date	Vulnerability Name	Required Action
	N/A

Metrics

Type	Version	Base score	Base severity	Vector
Secondary	3.1	5.4	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Primary	3.1	4.3	MEDIUM	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Type: Secondary

Version: 3.1

Base score: 5.4

Base severity: MEDIUM

Vector:

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Type: Primary

Version: 3.1

Base score: 4.3

Base severity: MEDIUM

Vector:

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CPE Matches

Mattermost, Inc.

>>mattermost_server>>Versions from 10.11.0(inclusive) to 10.11.10(exclusive)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

Mattermost, Inc.

>>mattermost_server>>Versions from 11.1.0(inclusive) to 11.1.3(exclusive)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

Mattermost, Inc.

>>mattermost_server>>Versions from 11.2.0(inclusive) to 11.2.2(exclusive)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

Weaknesses

CWE ID	Type	Source
CWE-303	Secondary	responsibledisclosure@mattermost.com

CWE ID: CWE-303

Type: Secondary

Source: responsibledisclosure@mattermost.com

References

Hyperlink	Source	Resource
https://mattermost.com/security-updates	responsibledisclosure@mattermost.com	Vendor Advisory

Hyperlink: https://mattermost.com/security-updates

Source: responsibledisclosure@mattermost.com

Resource:

Vendor Advisory

CISA Catalog

Metrics

CPE Matches

Weaknesses

Evaluator Description

Evaluator Impact

Evaluator Solution

Vendor Statements

References

Change History