SecuriTricks - CVE-2026-0999

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

Product(s) Impacted

Vendor	Product	Versions
Mattermost	Mattermost	11.1.0-11.1.2, 10.11.0-10.11.9, 11.2.0-11.2.1

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-303

Incorrect Implementation of Authentication Algorithm

The requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	mattermost	mattermost	11.1.0-11.1.2	/	/	/	/	/	/	/
a	mattermost	mattermost	10.11.0-10.11.9	/	/	/	/	/	/	/
a	mattermost	mattermost	11.2.0-11.2.1	/	/	/	/	/	/	/

References

https://mattermost.com/security-updates

CVSS Score

5.4 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: LOW
Scope: UNCHANGED
Confidentiality Impact: LOW
Integrity Impact: LOW
Availability Impact: NONE

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

View Vector String

Timeline

Published: Feb. 16, 2026, 10:16 a.m.
Last Modified: Feb. 16, 2026, 10:16 a.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-0999