CVE-2026-6343 — Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13,

CVE-2026-6343 — Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13,

CVE-2026-6343 — Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check public/private permissions which allows members without these permissions to access public playbooks via /get.. Mattermost Advisory ID: MMSA-2026-00591

What This Means For You

  • If your environment is affected by CWE-863, review your exposure and prioritize patching based on your environment. Monitor vendor advisories for CVE-2026-6343 updates and patches.

Related ATT&CK Techniques

🛡️ Detection Rules

4 rules · 6 SIEM formats

4 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.

high T1190 Initial Access

Web Application Exploitation Attempt — CVE-2026-6343

Sigma YAML — free preview
title: Web Application Exploitation Attempt — CVE-2026-6343
id: scw-2026-05-18-1
status: experimental
level: high
description: |
  Detects common exploitation patterns targeting web applications. Review CVE-2026-6343 advisories for specific indicators.
author: SCW Feed Engine (auto-generated)
date: 2026-05-18
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-6343/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri-query|contains:
        - '..'
        - 'SELECT'
        - 'UNION'
        - '<script'
        - 'cmd='
        - '/etc/passwd'
      condition: selection
falsepositives:
  - Legitimate activity from CVE-2026-6343

Source: Shimi's Cyber World · License & reuse

✓ Sigma · Splunk SPL Sentinel KQL Elastic QRadar AQL Wazuh Get rules for your SIEM →

Indicators of Compromise

IDTypeIndicator
CVE-2026-6343 vulnerability CVE-2026-6343
CWE-863 weakness CWE-863
Source & Attribution
Source PlatformNVD
ChannelNational Vulnerability Database
PublishedMay 18, 2026 at 12:16 UTC

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