CVE-2026-4055

MEDIUM

Insufficient permission validation on cross-team playbook run creation

Title source: cna
STIX 2.1

Description

Mattermost versions 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API request. Mattermost Advisory ID: MMSA-2026-00629

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00629
https://mattermost.com/security-updates

Scores

CVSS v3 4.3
EPSS 0.0015
EPSS Percentile 4.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-863
Status published
Products (7)
Mattermost/Mattermost 10.11.14
Mattermost/Mattermost 11.4.4
Mattermost/Mattermost 11.5.0 - 11.5.1
Mattermost/Mattermost 11.5.2
Mattermost/Mattermost 11.6.0
mattermost/mattermost 8.0.0-20260304132957-9f2616376582 - 8.0.0-20260320113102-f2b3d1c6a945Go
mattermost/mattermost_server 10.11.0 - 10.11.17
Published May 21, 2026
Tracked Since May 21, 2026