SecuriTricks - CVE-2026-6739

Description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656

Product(s) Impacted

Vendor	Product	Versions
Mattermost	Mattermost	11.6.0-11.6.1, 11.5.0-11.5.4, 10.11.0-10.11.16

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-863

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.

*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	11.6.0-11.6.1	/	/	/	/	/	/	/
a	mattermost	mattermost	11.5.0-11.5.4	/	/	/	/	/	/	/
a	mattermost	mattermost	10.11.0-10.11.16	/	/	/	/	/	/	/

References

https://mattermost.com/security-updates

CVSS Score

6.7 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: HIGH
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: LOW

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

View Vector String

Timeline

Published: June 12, 2026, 5:16 p.m.
Last Modified: June 12, 2026, 5:16 p.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-2026-6739