CVE-2017-18901
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 · uneditedAn issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. It allows attackers to discover a team invite ID by requesting a JSON document.
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 Server before versions 4.1.0, 4.0.4, and 3.10.3 contains an information disclosure vulnerability where unauthenticated attackers can discover team invite IDs by requesting a specific JSON document endpoint. The application fails to properly authorize access to this sensitive identifier information.
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< 3.10.3>= 4.0.0, < 4.0.4CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Mattermost Server versionRun the command `mattermost version` or check the server configuration files for the version string. On the server, you can also query the API endpoint `GET /api/v4/system/ping` or check the logs for version information.Affected if The installed version is less than 3.10.3, OR greater than or equal to 4.0.0 but less than 4.0.4.
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Verify team invite functionality is enabledCheck the Mattermost System Console settings under 'Team Settings' > 'Enable Open Server' or review the configuration file (config.json) for the `EnableOpenServer` setting and team creation settings.Affected if Team creation or team invite functionality is enabled on the server.
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Test access to team invite ID endpoint without authenticationSend an unauthenticated HTTP request to the JSON endpoint that returns team invite information. This typically involves requesting a team invite link or status endpoint without providing valid credentials.Affected if The server returns team invite IDs or sensitive team identifiers in the response without requiring authentication.
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Review API endpoint authorizationUse a browser or HTTP client to attempt access to team-related API endpoints such as `/api/v4/teams/<team_id>/invite/ids` or similar paths without logging in. Observe whether the response contains sensitive invite identifiers.Affected if The endpoint responds with team invite ID data to unauthenticated requests.
You are affected if your Mattermost Server version falls within the vulnerable ranges AND the team invite functionality is active AND the specific JSON endpoint exposes invite IDs without authorization checks.
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.
From vendor data3.10.34.0.4
Upgrade Mattermost Server to version 4.1.0, 4.0.4, 3.10.3 or later. Alternatively, implement proper authorization checks on JSON endpoints that return team invite IDs to ensure only authorized team members can access this information.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-18901 — 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-2017-18901 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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- Version or environment caveats, and links to real fixes
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