Detections
Analytics

SCA: security update for github.com/mattermost/mattermost-server, github.com/mattermost/mattermost/server/v8 (GHSA-5mr9-crcg-8wh2)

medium Tenable Self-Hosted Container Security Plugin ID 438953

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error
 responses when handling the /mute command which allows an authenticated team member to enumerate private
 channels they are not authorized to know about via differing error messages for nonexistent versus private
 channels. Mattermost Advisory ID: MMSA-2026-00588 (CVE-2026-21386)

Solution

Update the github.com/mattermost/mattermost-server library and its related packages to version 10.11.11 or later.

See Also

https://github.com/advisories/GHSA-5mr9-crcg-8wh2

Plugin Details

Severity: Medium

ID: 438953

Version: Revision 1.6

Type: Local

Family: SCA Checks

Published: 3/18/2026

Updated: 7/2/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

Vendor

Vendor Severity: Medium

CVSS v2

Risk Factor: Medium

Base Score: 4

Temporal Score: 3

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

CVSS Score Source: CVE-2026-21386

CVSS v3

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.8

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 3/16/2026

Vulnerability Publication Date: 3/16/2026

Reference Information

CVE: CVE-2026-21386

cwe: CWE-203