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MattermostApplication

CVE-2023-4106

MEDIUM · 6.5 CVSS v3.1 Published 2023-08-11
Fix available
A fix is available. Upgrade to 7.8.8 / 7.9.6 or later.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Mattermost fails to check if the requesting user is a guest before performing different actions to public playbooks, resulting a guest being able to view, join, edit, export and archive public playbooks.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is an authorization bypass vulnerability where Mattermost fails to validate whether a requesting user is a guest before allowing actions on public playbooks. The missing guest user check allows unauthorized guest accounts to view, join, edit, export, and archive public playbooks that should be restricted.

MitigationApply the vendor patch when available; meanwhile, review and restrict guest user permissions to sensitive playbooks or consider disabling guest accounts if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MattermostApplication
Affected:>= 7.8.0, < 7.8.8>= 7.9.0, < 7.9.6>= 7.10.0, < 7.10.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the installed Mattermost version
    Access the Mattermost System Console and navigate to About > Edition and License, or run the /version command in a channel. Compare the version number against the affected ranges: 7.8.0 through 7.8.7, 7.9.0 through 7.9.5, and 7.10.0 through 7.10.3
    Affected if The installed version is 7.8.0-7.8.7, 7.9.0-7.9.5, or 7.10.0-7.10.3
  2. Confirm guest access is enabled
    In the System Console, go to Authentication > Guest Access and verify whether the Enable guest access setting is turned on
    Affected if Guest access is enabled and the Mattermost version is in the affected range listed above
  3. Identify public playbooks in the environment
    Navigate to the Playbooks section in the main Mattermost navigation. Review the playbook list and identify any playbooks that are configured as Public (visible to anyone on the team or site)
    Affected if Public playbooks exist and guest access is enabled on an affected version
  4. Verify guest user permissions on public playbooks
    Log in as a guest user account and attempt to access a public playbook. Test whether you can view, join, edit, export, or archive the playbook. Alternatively, review the playbook membership settings in the Playbooks section
    Affected if A guest user can view, join, edit, export, or archive a public playbook that they should not have access to

Your environment is affected if Mattermost is version 7.8.0-7.8.7, 7.9.0-7.9.5, or 7.10.0-7.10.3 AND guest access is enabled AND public playbooks exist that should not be accessible to guest accounts.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.8.8 / 7.9.6 / 7.10.4 or later
Fixed in 7.8.87.9.67.10.4
Interim mitigation

Apply the vendor patch when available; meanwhile, review and restrict guest user permissions to sensitive playbooks or consider disabling guest accounts if not required.

Recommended fix High confidence

Upgrade to Mattermost 7.10.4 or later (or 7.8.8 if on 7.8.x branch, 7.9.6 if on 7.9.x branch)

  1. 1. Back up your Mattermost database and configuration files before upgrading.
  2. 2. Review Mattermost upgrade documentation for your deployment type (e.g., Ansible, Docker, Kubernetes, manual).
  3. 3. For Mattermost Self-Hosted: Download the latest fixed version (7.10.4 or later) from https://mattermost.com/download/.
  4. 4. For Docker deployments: Update your image tag to the fixed version (e.g., mattermost/mattermost-team-edition:7.10.4).
  5. 5. For Kubernetes: Update your deployment manifest with the new image version.
  6. 6. Restart the Mattermost server to apply the changes.
  7. 7. Verify the upgrade by logging in and confirming guest users can no longer perform unauthorized actions on public playbooks.
  8. 8. Test that legitimate functionality (playbook creation, management by proper users) still works correctly.
Caveat Review Mattermost 7.10 release notes for any behavior changes; minor version upgrades typically have minimal breaking changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mattermost Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
26.0 hours of engineering $4,580
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,328.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-4106 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data