Detections
Analytics

Mattermost Server 10.5.x < 10.5.12 / 10.11.x 10.11.4 / 11.0.0 Missing Authorization (MMSA-2025-00518)

medium Nessus Plugin ID 275839

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Synopsis

The remote host is missing a security update.

Description

The version of Mattermost Server installed on the remote host is affected by a vulnerability as referenced in the MMSA-2025-00518 advisory.

 - Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata and channel membership information from other teams via the API endpoint. (CVE-2025-11777)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Mattermost Server version 10.5.12, 10.11.4, 11.0.0 or later.

See Also

https://mattermost.com/security-updates/

Plugin Details

Severity: Medium

ID: 275839

File Name: mattermost_server_MMSA-2025-00518.nasl

Version: 1.2

Type: remote

Family: CGI abuses

Published: 11/20/2025

Updated: 11/21/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.2

CVSS v2

Risk Factor: Medium

Base Score: 4

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N

CVSS Score Source: CVE-2025-11777

CVSS v3

Risk Factor: Medium

Base Score: 4.3

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Vulnerability Information

CPE: cpe:/a:mattermost:mattermost_server

Required KB Items: installed_sw/Mattermost Server

Patch Publication Date: 11/13/2025

Vulnerability Publication Date: 11/13/2025

Reference Information

CVE: CVE-2025-11777

IAVA: 2025-A-0866