CVE-2026-93847 PUBLISHED

Improper post type validation on scheduled post endpoints

Assigner: Mattermost
Reserved: 18.09.2026 Published: 26.10.2026 Updated: 26.10.2026

Mattermost versions 11.7.x <= 11.7.10 fail to validate reserved system post types on the scheduled post creation and publication paths which allows an authenticated channel member to publish messages rendering as trusted system events via the scheduled post endpoint.. Mattermost Advisory ID: MMSA-2026-00732

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
CVSS Score: 3.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	Low	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	Mattermost
Product	Mattermost
Versions	Default: unaffected affected from 11.7.0 to 11.7.10 (incl.) Version 11.11.0 is unaffected Version 11.7.11 is unaffected

Solutions

Update Mattermost to versions 11.11.0, 11.7.11 or higher.

Credits

arang finder

References

MMSA-2026-00732

Problem Types

CWE-863: Incorrect Authorization CWE