CVE-2024-6428
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 9.8.0, 9.7.x <= 9.7.4, 9.6.x <= 9.6.2, 9.5.x <= 9.5.5 fail to prevent specifying a RemoteId when creating a new user which allows an attacker to specify both a remoteId and the user ID, resulting in creating a user with a user-defined user ID. This can cause some broken functionality in User Management such administrative actions against the user not working.
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 confidenceMattermost fails to validate input during user creation, allowing attackers to specify both a remoteId and arbitrary user ID. This improper input validation results in users being created with attacker-controlled IDs, breaking User Management functionality such as administrative actions.
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>= 9.5.0, < 9.5.6>= 9.6.0, < 9.6.3>= 9.7.0, < 9.7.5>= 9.8.0, < 9.8.1CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Mattermost versionRun 'mattermost version' or inspect the Mattermost server configuration file for the version stringAffected if The version falls within >=9.5.0,<9.5.6 OR >=9.6.0,<9.6.3 OR >=9.7.0,<9.7.5 OR >=9.8.0,<9.8.1
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Review user creation permissionsIn Mattermost System Console, navigate to Users and Teams > User Creation and verify which roles have permission to create usersAffected if Users other than System Admins have user creation permissions and the version is affected
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Inspect for unexpected users with non-standard IDsQuery the Users table in the Mattermost database or use the Mattermost API to list all users and examine their IDs for anomalies such as extremely long numeric strings or unexpected formatsAffected if Users exist with IDs that are not standard GUIDs or sequential integers, indicating attacker-controlled IDs
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Review user creation audit logsCheck Mattermost audit logs and server logs for API calls to /api/v4/users that include both a remoteId field and a custom id field in the request payloadAffected if Audit logs show user creation requests with both remoteId and attacker-specified user IDs present
A user is affected if their Mattermost version is within any of the affected ranges AND they have users with non-standard or attacker-controlled IDs in their system.
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 · scoped9.5.69.6.39.7.5
Upgrade to a patched version of Mattermost. Until then, restrict user creation permissions to trusted administrators and monitor for unexpected user accounts with non-standard IDs.
9.8.1 (or 9.5.6/9.6.3/9.7.5 depending on your branch)
- Identify the currently running Mattermost version from the affected list (9.5.0-9.5.5, 9.6.0-9.6.2, 9.7.0-9.7.4, or 9.8.0)
- Determine the appropriate upgrade target based on your current major.minor version
- For 9.5.x: upgrade to 9.5.6
- For 9.6.x: upgrade to 9.6.3
- For 9.7.x: upgrade to 9.7.5
- For 9.8.x: upgrade to 9.8.1
- Follow Mattermost upgrade documentation to perform the upgrade
- After upgrade, verify the system is functioning normally and test user management operations
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-6428 — 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-2024-6428 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
- No spam, self-promotion, credentials, or personal data