Mattermost server missing request body size limit on plugin routes allows denial of service by an authenticated user
Summary
| CVE | CVE-2026-96260 |
|---|---|
| State | PUBLISHED |
| Assigner | Mattermost |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-22 21:17:35 UTC |
| Updated | 2026-09-22 21:17:35 UTC |
| 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 |
Risk And Classification
Primary CVSS: v3.1 6.5 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Problem Types: CWE-789 | CWE-789 CWE-789: Memory Allocation with Excessive Size Value
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mattermost | Mattermost | affected 11.9.0 11.9.1 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.8.0 11.8.5 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.7.0 11.7.10 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.10.0 11.10.1 semver | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.11.0 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.9.2 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.8.6 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.7.11 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.10.2 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mattermost.com/security-updates | [email protected] | mattermost.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: alimursaliyev (en)
Additional Advisory Data
Solutions
CNA: Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.
There are currently no legacy QID mappings associated with this CVE.