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Mattermost ServerApplication · Mattermost

CVE-2023-3586

MEDIUM · 5.4 CVSS v3.1 Published 2023-07-17
Fix available
A fix is available. Upgrade to 7.8.7 / 7.9.5 or later.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable 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 disable public Boards after the "Enable Publicly-Shared Boards" configuration option is disabled, resulting in previously-shared public Boards to remain accessible.

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

In Mattermost, when an administrator disables the 'Enable Publicly-Shared Boards' configuration option, existing boards that were previously shared publicly remain accessible via their public links. The server fails to invalidate or revoke previously-generated shared board URLs when the feature is toggled off.

MitigationAdministrators should manually audit and revoke access to any boards that were shared while the feature was enabled, and the development team should implement code to automatically invalidate all shared board links when the configuration is disabled.

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
Mattermost ServerApplication
Affected:>= 7.8.0, < 7.8.7>= 7.9.0, < 7.9.5>= 7.10.0, < 7.10.3

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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 Mattermost Server version
    Run 'mattermost version' or check the About section in the System Console to determine the installed server version
    Affected if The installed version falls within >= 7.8.0 to < 7.8.7, >= 7.9.0 to < 7.9.5, or >= 7.10.0 to < 7.10.3
  2. Verify current shared boards configuration
    Navigate to System Console > Boards > Settings and locate the 'Enable Publicly-Shared Boards' toggle. Check whether it is currently disabled.
    Affected if The toggle is currently disabled but was previously enabled in older versions
  3. Identify boards with active shared links
    Query the database: 'SELECT Id, TeamId, ChannelId, CreateAt FROM Boards WHERE Type = 8' (Type 8 indicates a shared board). Alternatively, use the Boards API endpoint GET /api/v1/boards to list boards and check for 'shared' property.
    Affected if There exist boards with shared links in the database or API response when the feature should be disabled
  4. Test if shared board URLs remain accessible
    Take a known previously-shared board URL (format: https://<server>/boards/<board-id>) and attempt to access it while logged out or in an incognito window, after confirming the feature is disabled in settings.
    Affected if The board is accessible via its public link despite the feature being disabled in configuration

A user is affected if their Mattermost Server version is within the affected ranges AND the Enable Publicly-Shared Boards feature was ever enabled AND boards with shared links still exist or remain accessible after the feature is toggled off.

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 7.8.7 / 7.9.5 / 7.10.3 or later
Fixed in 7.8.77.9.57.10.3
Interim mitigation

Administrators should manually audit and revoke access to any boards that were shared while the feature was enabled, and the development team should implement code to automatically invalidate all shared board links when the configuration is disabled.

Recommended fix High confidence

7.10.3 (or 7.8.7/7.9.5 depending on current branch)

  1. Upgrade Mattermost Server to version 7.8.7, 7.9.5, or 7.10.3 (recommended: 7.10.3)
  2. After upgrade, navigate to Mattermost Boards settings and verify the 'Enable Publicly-Shared Boards' configuration option is set to the desired state
  3. Manually review and revoke any existing public board shares that should no longer be accessible using the Boards UI or API
  4. Verify that previously-shared public Boards are no longer accessible when the configuration is disabled
Caveat Review Mattermost release notes for version 7.10.3 for any compatibility notes or breaking changes before upgrading

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2023-3586 in production — separate from our analysis above.

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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