---
id: CVE-2026-19600
title: >-
  Mattermost logs plaintext authentication tokens in debug-level server logs on
  failed auth attempts
summary: >-
  Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10,
  11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them
  to server log entries, which allows an attacker with access to server logs to
  obtain…
severity: medium
cvss: 4.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-532
vendor: Mattermost
product: Mattermost
affected:
  - Mattermost >= 11.9.0 <= 11.9.1
  - Mattermost >= 11.8.0 <= 11.8.5
  - Mattermost >= 11.7.0 <= 11.7.10
  - Mattermost >= 11.10.0 <= 11.10.1
published: '2026-10-16'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T07:07:17.899Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-19600'
references:
  - url: 'https://mattermost.com/security-updates'
    label: MMSA-2026-00763
tags:
  - cve.org
ingestedAt: '2026-10-16T08:02:23.122Z'
---

## Overview

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize authentication tokens before writing them to server log entries, which allows an attacker with access to server logs to obtain valid session tokens or OAuth access tokens and impersonate authenticated users via the debug-level Mattermost server log.. Mattermost Advisory ID: MMSA-2026-00763

## Affected

- `Mattermost >= 11.9.0 <= 11.9.1`
- `Mattermost >= 11.8.0 <= 11.8.5`
- `Mattermost >= 11.7.0 <= 11.7.10`
- `Mattermost >= 11.10.0 <= 11.10.1`

## Remediation

Update Mattermost to versions 11.11.0, 11.9.2, 11.8.6, 11.7.11, 11.10.2 or higher.