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Mattermost ServerApplication · Mattermost

CVE-2024-28949

MEDIUM · 6.5 CVSS v3.1 Published 2024-04-05
Fix available
A fix is available. Upgrade to 8.1.11 / 9.3.3 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 Server versions 9.5.x before 9.5.2, 9.4.x before 9.4.4, 9.3.x before 9.3.3, 8.1.x before 8.1.11 don't limit the number of user preferences which allows an attacker to send a large number of user preferences potentially causing denial of service.

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

Mattermost Server versions prior to 9.5.2, 9.4.4, 9.3.3, and 8.1.11 lack proper input validation on user preferences, allowing authenticated attackers to submit an unlimited number of preferences. This can exhaust server resources (memory, database storage) leading to denial of service.

MitigationUpgrade Mattermost Server to version 9.5.2, 9.4.4, 9.3.3, or 8.1.11 or later which implements limits on user preference counts.

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:>= 8.1.0, < 8.1.11>= 9.3.0, < 9.3.3>= 9.4.0, < 9.4.4>= 9.5.0, < 9.5.2

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
None
Integrity
None
Availability
High

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

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. Identify Mattermost Server version
    Run 'mattermost version' or check the Mattermost config file (config.json) for the Version field under ServiceSettings, or query the server API at /api/v4/system/stats/remote
    Affected if The installed version falls within any of these ranges: 8.1.0-8.1.10, 9.3.0-9.3.2, 9.4.0-9.4.3, or 9.5.0-9.5.1
  2. Verify user preferences API accessibility
    Confirm the Mattermost server has the user preferences endpoint (POST /api/v4/users/{user_id}/preferences) exposed and accessible to authenticated users
    Affected if Any authenticated user can access the preferences API without rate limiting or count restrictions
  3. Check database for preference count anomalies
    Query the Preferences table in the database: SELECT user_id, COUNT(*) as pref_count FROM Preferences GROUP BY user_id HAVING COUNT(*) > 1000; (adjust threshold based on expected normal usage)
    Affected if Any user has an unusually high number of preference records (thousands+) indicating the vulnerability may have been exploited
  4. Review server logs for preference spam
    Search Mattermost server logs for repeated POST requests to /api/v4/users/*/preferences or error messages related to preference storage
    Affected if Logs show high volume of preference creation requests from a single user in a short timeframe

A user is affected if their Mattermost Server version is 8.1.0-8.1.10, 9.3.0-9.3.2, 9.4.0-9.4.3, or 9.5.0-9.5.1 AND they observe excessive user preference records in the database or unusual preference-related API activity.

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 8.1.11 / 9.3.3 / 9.4.4 or later
Fixed in 8.1.119.3.39.4.4
Interim mitigation

Upgrade Mattermost Server to version 9.5.2, 9.4.4, 9.3.3, or 8.1.11 or later which implements limits on user preference counts.

Recommended fix High confidence

9.5.2 (or your nearest corresponding fixed release: 8.1.11, 9.3.3, or 9.4.4)

  1. 1. Back up your current Mattermost Server data and configuration
  2. 2. Schedule a maintenance window for the upgrade
  3. 3. Download the appropriate fixed version for your current installation (8.1.11, 9.3.3, 9.4.4, or 9.5.2)
  4. 4. Follow Mattermost's standard upgrade documentation for your deployment method
  5. 5. Verify the upgrade was successful by checking the server version in the system console
  6. 6. Test that the application is functioning normally post-upgrade

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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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-2024-28949 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