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Mattermost ServerApplication · Mattermost

CVE-2024-23493

MEDIUM · 6.5 CVSS v3.1 Published 2024-02-29
Fix available
A fix is available. Upgrade to 8.1.9 / 9.2.5 or later.
See remediation →
71/100
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 properly authorize the requests fetching team associated AD/LDAP groups, allowing a user to fetch details of AD/LDAP groups of a team that they are not a member of. 

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 · moderate confidence

Mattermost contains an IDOR (Insecure Direct Object Reference) vulnerability where the API endpoint for fetching team-associated AD/LDAP groups does not properly validate that the requesting user is a member of the target team. This allows authenticated users to enumerate AD/LDAP group details for teams they do not belong to, resulting in unauthorized information disclosure.

MitigationApply the Mattermost security update (likely version 9.x.x) that implements proper authorization checks to verify team membership before returning AD/LDAP group details. Until patched, monitor API access logs for unauthorized team group enumeration attempts.

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:< 8.1.9>= 9.0.0, < 9.2.5>= 9.4.0, < 9.4.2= 9.3.0

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
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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 'sudo mattermost version' or check the Mattermost configuration file for the server version string
    Affected if Version is < 8.1.9, or >= 9.0.0 and < 9.2.5, or >= 9.4.0 and < 9.4.2, or exactly 9.3.0
  2. Verify AD/LDAP integration is enabled
    Check Mattermost System Console under 'AD/LDAP' settings, or inspect config.json for 'LdapSettings' with 'Enable': true
    Affected if AD/LDAP authentication and group synchronization is actively configured and enabled
  3. Confirm multiple teams exist
    Query the API endpoint /api/v4/teams or check System Console for more than one team configured
    Affected if Multiple teams are present in the Mattermost instance, enabling cross-team enumeration
  4. Review API access logs for team group enumeration
    Search Mattermost logs (typically in /var/log/mattermost/) for API calls to /api/v4/teams/*/groups that originate from users not member of the requested team
    Affected if API requests to team-associated group endpoints are observed from users outside the target team

A user is affected if running a vulnerable Mattermost Server version with AD/LDAP enabled and multiple teams configured, where unauthorized enumeration of team-specific AD/LDAP groups may have occurred.

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 8.1.9 / 9.2.5 / 9.4.2 or later
Fixed in 8.1.99.2.59.4.2
Interim mitigation

Apply the Mattermost security update (likely version 9.x.x) that implements proper authorization checks to verify team membership before returning AD/LDAP group details. Until patched, monitor API access logs for unauthorized team group enumeration attempts.

Recommended fix High confidence

8.1.9 (for 8.x) | 9.2.5 (for 9.0-9.2) | 9.3.1 (for 9.3) | 9.4.2 (for 9.4) - or latest stable release in your major version branch

  1. 1. Identify your current Mattermost Server version by checking the system console or running 'mmctl version'
  2. 2. For 8.x branch (versions < 8.1.9): Upgrade to version 8.1.9 or later
  3. 3. For 9.0.x-9.2.x branch (versions >= 9.0.0 and < 9.2.5): Upgrade to version 9.2.5 or later
  4. 4. For 9.3.x branch (version 9.3.0): Upgrade to version 9.3.1 or later
  5. 5. For 9.4.x branch (versions >= 9.4.0 and < 9.4.2): Upgrade to version 9.4.2 or later
  6. 6. After upgrade, verify that AD/LDAP group synchronization is working correctly and that users can only access groups for teams they are members of
  7. 7. Review audit logs to confirm the vulnerability is no longer exploitable
Caveat Review Mattermost release notes for your upgrade path as minor version upgrades may include configuration or feature changes; test in staging environment before production deployment

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2024-23493 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