CVE-2026-4055

Insufficient permission validation on cross-team playbook run creation

State: Published
Severity: 4.3 Medium
Published: May 21, 2026
Updated: May 21, 2026
Reserved: Mar 12, 2026

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

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N	Mattermost

Weaknesses

CWE-863 Incorrect Authorization

Affected Products

Product	Versions
MattermostMattermost	11.5.0 through 11.5.1Affected 11.6.0Not affected 11.5.2Not affected 10.11.14Not affected 11.4.4Not affected

References

MMSA-2026-00629vendor-advisory

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