CVE-2026-96260

Mattermost server missing request body size limit on plugin routes allows denial of service by an authenticated user

State: Published
Severity: 6.5 Medium
Published: Sep 22, 2026
Updated: Sep 23, 2026
Reserved: Sep 22, 2026

Description

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to enforce a request body size limit during CSRF validation of plugin requests which allows an authenticated user to exhaust server memory and cause a denial of service via a large request body sent to a plugin endpoint.. Mattermost Advisory ID: MMSA-2026-00775

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	Mattermost

Weaknesses

CWE-789 Memory Allocation with Excessive Size Value

Affected Products

Product	Versions
MattermostMattermost	11.9.0 through 11.9.1Affected 11.8.0 through 11.8.5Affected 11.7.0 through 11.7.10Affected 11.10.0 through 11.10.1Affected 11.11.0Not affected 11.9.2Not affected 11.8.6Not affected 11.7.11Not affected 11.10.2Not affected

References

MMSA-2026-00775vendor-advisory

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