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

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Mattermost Mattermost unaffected
Version Status Constraints
11.9.0 affected ≤ 11.9.1
11.8.0 affected ≤ 11.8.5
11.7.0 affected ≤ 11.7.10
11.10.0 affected ≤ 11.10.1
11.11.0 unaffected —
11.9.2 unaffected —
11.8.6 unaffected —
11.7.11 unaffected —
11.10.2 unaffected —

No data.

No data.

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No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.

Workaround

No workaround given by the vendor.

References
Link Providers
https://mattermost.com/security-updates cve-icon cve-icon
History

Tue, 22 Sep 2026 20:45:00 +0000

Type Values Removed Values Added
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
Title Mattermost server missing request body size limit on plugin routes allows denial of service by an authenticated user
Weaknesses CWE-789
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2026-09-22T20:34:49.141Z

Reserved: 2026-09-22T20:00:26.276Z

Link: CVE-2026-96260

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-22T21:17:35.027

Modified: 2026-09-22T21:17:35.027

Link: CVE-2026-96260

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-22T21:30:20Z

Weaknesses