Guest users can view group member IDs without respecting view restrictions
Summary
| CVE | CVE-2026-3115 |
|---|---|
| State | PUBLISHED |
| Assigner | Mattermost |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-26 17:16:42 UTC |
| Updated | 2026-03-30 19:40:01 UTC |
| Description | Mattermost versions 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 fail to apply view restrictions when retrieving group member IDs, which allows authenticated guest users to enumerate user IDs outside their allowed visibility scope via the group retrieval endpoint.. Mattermost Advisory ID: MMSA-2026-00594 |
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:L/I:N/A:N
Problem Types: CWE-863 | CWE-863 CWE-863: Incorrect 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:L/I:N/A:N |
| 3.1 | CNA | CVSS | 4.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/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 11.2.0 11.2.2 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 10.11.0 10.11.10 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.4.0 11.4.0 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.3.0 11.3.1 semver | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.5.0 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.2.3 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 10.11.11 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.4.1 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.3.2 | 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: winfunc (en)
Additional Advisory Data
Solutions
CNA: Update Mattermost to versions 11.5.0, 11.2.3, 10.11.11, 11.4.1, 11.3.2 or higher.
There are currently no legacy QID mappings associated with this CVE.