CVE-2024-2447
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 · uneditedMattermost versions 8.1.x before 8.1.11, 9.3.x before 9.3.3, 9.4.x before 9.4.4, and 9.5.x before 9.5.2 fail to authenticate the source of certain types of post actions, allowing an authenticated attacker to create posts as other users via a crafted post action.
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 confidenceMattermost fails to authenticate the source of certain post actions, allowing an authenticated attacker to send crafted requests that create posts as other users. This is an authorization/IDOR vulnerability in the post action handling logic.
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>= 8.1.0, < 8.1.11>= 9.3.0, < 9.3.3>= 9.4.0, < 9.4.4>= 9.5.0, < 9.5.2CVSS 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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Determine Mattermost Server versionLog into the Mattermost System Console and go to Environment > Web Server, or run the command 'mattermost version' from the server CLI. The version is displayed in the output as 'Version: X.Y.Z'.Affected if The installed version falls within any of these ranges: 8.1.0 to 8.1.10, 9.3.0 to 9.3.2, 9.4.0 to 9.4.3, or 9.5.0 to 9.5.1.
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Verify post actions are accessiblePost actions are a built-in feature triggered from message buttons in posts. No explicit enable/disable toggle exists for this core functionality in standard Mattermost deployments. Confirm the server handles interactive post elements.Affected if Post actions are processed by the server (standard behavior for all affected versions).
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Review audit logs for unauthorized post actionsCheck Mattermost logs in the System Console under Audit Logs, or examine the server log files (typically in /var/log/mattermost/). Look for POST requests to /api/v4/actions/dialogs or /api/v4/posts/{post_id}/actions from users who should not be able to impersonate other users.Affected if Audit logs show post action requests with user IDs that do not match the authenticated session token, indicating potential exploitation.
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Inspect for anomalous posts created via actionsQuery the database or use Mattermost search (using 'from:<username> in:<channel>') to identify posts that were created by a user but appear to have originated from a different user's context or contain content the user could not normally create.Affected if Posts exist where the actor_user_id in the database differs from the actual creator's expected permissions, suggesting IDOR exploitation.
You are affected if your Mattermost Server version is 8.1.0 through 8.1.10, 9.3.0 through 9.3.2, 9.4.0 through 9.4.3, or 9.5.0 through 9.5.1, and post actions have been used on your server.
Generated from the published advisory. Verify against your own configuration.
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 · scoped8.1.119.3.39.4.4
Update Mattermost to version 8.1.11, 9.3.3, 9.4.4, 9.5.2 or later to patch the missing source authentication in post actions.
Upgrade to the latest patch version in your current branch (8.1.11, 9.3.3, 9.4.4, or 9.5.2), or upgrade to the most recent stable release (9.5.2 or later)
- 1. Identify the current Mattermost Server version by checking the system console or running 'mattermost version'
- 2. Determine which version branch you are currently on (8.1.x, 9.3.x, 9.4.x, or 9.5.x)
- 3. Download the appropriate fixed version for your branch: 8.1.11, 9.3.3, 9.4.4, or 9.5.2
- 4. Back up your Mattermost database and configuration files before upgrading
- 5. Stop the Mattermost server service
- 6. Install the new version using your package manager or by replacing the binary
- 7. Start the Mattermost server service
- 8. Verify the upgrade was successful by checking the version in the system console
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-2447 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-2447 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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