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MattermostApplication

CVE-2024-39361

MEDIUM · 5.4 CVSS v3.1 Published 2024-07-03
Fix available
A fix is available. Upgrade to 9.5.6 / 9.6.3 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 versions 9.8.0, 9.7.x <= 9.7.4, 9.6.x <= 9.6.2 and 9.5.x <= 9.5.5 fail to prevent users from specifying a RemoteId for their posts which allows an attacker to specify both a remoteId and the post ID, resulting in creating a post with a user-defined post ID. This can cause some broken functionality in the channel or thread with user-defined posts

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 versions 9.5.x through 9.8.0 contain an IDOR vulnerability where the application does not validate or restrict user-specified RemoteId and post ID parameters during post creation. This allows authenticated users to create posts with arbitrary identifiers, potentially causing broken functionality in channels or threads.

MitigationApply vendor patches by upgrading to Mattermost versions 9.8.1, 9.7.5, 9.6.3, or 9.5.6 or later which enforce proper validation of RemoteId and post ID parameters.

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:>= 9.5.0, < 9.5.6>= 9.6.0, < 9.6.3>= 9.7.0, < 9.7.4>= 9.8.0, < 9.8.1

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
Low
Availability
Low

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

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. Determine installed Mattermost version
    Check the Mattermost server version by logging into the System Console and navigating to 'About' > 'Mattermost', or by running: curl -H 'Authorization: Bearer <admin_token>' https://<mattermost_url>/api/v4/system/about
    Affected if The installed version falls within any of these ranges: 9.5.0 to 9.5.5, 9.6.0 to 9.6.2, 9.7.0 to 9.7.3, or 9.8.0
  2. Verify the vulnerability exists in the detected version
    Compare the installed version number to the affected ranges: >= 9.5.0 and < 9.5.6, OR >= 9.6.0 and < 9.6.3, OR >= 9.7.0 and < 9.7.4, OR >= 9.8.0 and < 9.8.1
    Affected if The version matches any of the affected ranges listed above
  3. Confirm authenticated user access to post creation API
    Verify that regular authenticated users have access to the posts API endpoint. In Mattermost, authenticated users can create posts via POST /api/v4/posts. Confirm this endpoint is accessible to non-admin users in your environment.
    Affected if Authenticated users can access the post creation endpoint, which is the default configuration in Mattermost

You are affected if your Mattermost server version is 9.5.0-9.5.5, 9.6.0-9.6.2, 9.7.0-9.7.3, or 9.8.0, and authenticated users can create posts (standard configuration).

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 9.5.6 / 9.6.3 / 9.7.4 or later
Fixed in 9.5.69.6.39.7.4
Interim mitigation

Apply vendor patches by upgrading to Mattermost versions 9.8.1, 9.7.5, 9.6.3, or 9.5.6 or later which enforce proper validation of RemoteId and post ID parameters.

Recommended fix High confidence

Upgrade to Mattermost 9.5.6, 9.6.3, 9.7.4, or 9.8.1 (depending on your current branch)

  1. 1. Identify the currently installed Mattermost version by checking the system settings or running 'mattermost version'
  2. 2. Determine which affected version branch your installation falls into (9.5.x, 9.6.x, 9.7.x, or 9.8.x)
  3. 3. For Mattermost 9.5.x: Upgrade to version 9.5.6 or later
  4. 4. For Mattermost 9.6.x: Upgrade to version 9.6.3 or later
  5. 5. For Mattermost 9.7.x: Upgrade to version 9.7.4 or later
  6. 6. For Mattermost 9.8.0: Upgrade to version 9.8.1 or later
  7. 7. After upgrade, verify the fix by testing post creation functionality to confirm proper RemoteId handling
Caveat Standard minor version upgrade; review Mattermost release notes for any deprecation notices

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

Fix this in Mattermost 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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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-2024-39361 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