Mattermost fails to enforce create_post permission when editing posts
Summary
| CVE | CVE-2026-3637 |
|---|---|
| State | PUBLISHED |
| Assigner | Mattermost |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-18 08:16:14 UTC |
| Updated | 2026-05-19 17:34:01 UTC |
| Description | Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check the create_post channel permission during post edit operations which allows an authenticated attacker with revoked posting privileges to modify their existing posts via direct API requests to the post update and patch endpoints.. Mattermost Advisory ID: MMSA-2026-00627 |
Risk And Classification
Primary CVSS: v3.1 4.3 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.000310000 probability, percentile 0.092620000 (date 2026-05-26)
Problem Types: CWE-862 | CWE-862 CWE-862: Missing Authorization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 4.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 4.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Mattermost | Mattermost Server | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mattermost | Mattermost | affected 11.5.0 11.5.1 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 10.11.0 10.11.13 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.4.0 11.4.3 semver | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.6.0 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.5.2 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 10.11.14 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.4.4 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mattermost.com/security-updates | [email protected] | mattermost.com | Vendor Advisory |
| 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: 0x7oda7123 (en)
Additional Advisory Data
Solutions
CNA: Update Mattermost to versions 11.6.0, 11.5.2, 10.11.14, 11.4.4 or higher.
There are currently no legacy QID mappings associated with this CVE.