Detections
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SCA: security update for github.com/mattermost/mattermost-server, github.com/mattermost/mattermost/server/v8 (GHSA-xvcx-mgpc-5xh3)

medium Tenable Self-Hosted Container Security Plugin ID 442573

Description

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

 - Mattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the
 burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-
 on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID:
 MMSA-2026-00636 (CVE-2026-6339)

Solution

Update the github.com/mattermost/mattermost/server/v8 library and its related packages to version 11.4.4 or later.

See Also

https://github.com/advisories/GHSA-xvcx-mgpc-5xh3

Plugin Details

Severity: Medium

ID: 442573

Version: Revision 1.1

Type: Local

Family: SCA Checks

Published: 6/2/2026

Updated: 6/2/2026

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-2026-6339

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: 5/18/2026

Vulnerability Publication Date: 5/18/2026

Reference Information

CVE: CVE-2026-6339

cwe: CWE-346