CVE-2026-3115

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

CVSS v3 4.3 MEDIUM

4.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.8 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://mattermost.com/security-updates	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server::::::::
	cpe:2.3:a:mattermost:mattermost_server:11.4.0:::::::*

History

30 Mar 2026, 19:40

Type	Values Removed	Values Added
CPE		cpe:2.3:a:mattermost:mattermost_server:::::::: cpe:2.3:a:mattermost:mattermost_server:11.4.0:::::::*
First Time		Mattermost mattermost Server Mattermost
References	~~() https://mattermost.com/security-updates -~~	() https://mattermost.com/security-updates - Vendor Advisory

Information

Published : 2026-03-26 17:16

Updated : 2026-03-30 19:40

NVD link : CVE-2026-3115

Mitre link : CVE-2026-3115

CVE.ORG link : CVE-2026-3115

JSON object : View

Products Affected

mattermost

mattermost_server

CWE

CWE-863

Incorrect Authorization

{"id": "CVE-2026-3115", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 2.8}]}, "published": "2026-03-26T17:16:42.660", "references": [{"url": "https://mattermost.com/security-updates", "tags": ["Vendor Advisory"], "source": "responsibledisclosure@mattermost.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "responsibledisclosure@mattermost.com", "description": [{"lang": "en", "value": "CWE-863"}]}], "descriptions": [{"lang": "en", "value": "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"}, {"lang": "es", "value": "Las versiones de Mattermost 11.2.x <= 11.2.2, 10.11.x <= 10.11.10, 11.4.x <= 11.4.0, 11.3.x <= 11.3.1 no aplican las restricciones de visualizaci\u00f3n al recuperar los IDs de miembros de grupo, lo que permite a los usuarios invitados autenticados enumerar los IDs de usuario fuera de su \u00e1mbito de visibilidad permitido a trav\u00e9s del endpoint de recuperaci\u00f3n de grupo. ID de Aviso de Mattermost: MMSA-2026-00594"}], "lastModified": "2026-03-30T19:40:01.770", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B6E5F368-358C-429B-8F04-3C8DF4A71A91", "versionEndExcluding": "10.11.11", "versionStartIncluding": "10.11.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7F64C167-943D-4F3F-9374-BCC8DECB3881", "versionEndExcluding": "11.2.3", "versionStartIncluding": "11.2.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "805ECFFC-82FD-4754-AF95-32167E1D41CB", "versionEndExcluding": "11.3.2", "versionStartIncluding": "11.3.0"}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:11.4.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7B6A1FE2-D980-4755-A838-190A53A4D62B"}], "operator": "OR"}]}], "sourceIdentifier": "responsibledisclosure@mattermost.com"}