CVE-2026-13417

Boards plugin denial of service via unvalidated block fields.properties

State: Published
Severity: 4.3 Medium
Published: Sep 14, 2026
Updated: Sep 14, 2026
Reserved: Jun 26, 2026

Description

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate the type of `fields.properties` on block creation which allows an authenticated user with editor access to a board to crash the Boards plugin worker and trigger a denial of service via a child block whose `fields.properties` is a non-object value. Mattermost Advisory ID: MMSA-2026-00710

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:N/A:L	Mattermost

Weaknesses

CWE-754 Improper Check for Unusual or Exceptional Conditions

Affected Products

Product	Versions
MattermostMattermost	11.9.0 through 11.9.0Affected 11.8.0 through 11.8.4Affected 11.7.0 through 11.7.7Affected 10.11.0 through 10.11.22Affected 11.10.0Not affected 11.9.1Not affected 11.8.5Not affected 11.7.8Not affected 10.11.23Not affected

References

MMSA-2026-00710vendor-advisory

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.