CVE-2017-18919
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 3.7.0 and 3.6.3. Attackers can use the API for unauthenticated team creation.
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 Server before versions 3.7.0 and 3.6.3 contains an API vulnerability that allows unauthenticated attackers to create teams via the API endpoint, bypassing proper authentication controls.
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< 3.6.3CVSS 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
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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.
-
Identify Mattermost Server versionCheck the version file typically located at /opt/mattermost/version.txt or look at the version field in the Mattermost config file at /opt/mattermost/config/config.jsonAffected if The installed version is any release prior to 3.6.3 or 3.7.0 (e.g., 3.6.0, 3.5.x, etc.)
-
Verify API service is listeningCheck if the Mattermost API service is running and listening on its configured port (default 8000). Use command: netstat -tlnp | grep 8000 or ss -tlnp | grep 8000Affected if The API service is actively listening and accessible
-
Confirm API is network-accessibleReview network configuration or firewall rules to determine if the API port (8000 or configured alternative) is exposed to untrusted networks. Check /etc/iptables/rules.v4 or firewall-cmd --list-all for external access rulesAffected if The API port is accessible from outside the trusted network or from untrusted IP addresses
-
Test authentication enforcement on team creation APISend a POST request to the team creation endpoint (e.g., http://YOUR_SERVER/api/v1/teams) with no authentication headers. Use: curl -X POST http://localhost:8000/api/v1/teams -H 'Content-Type: application/json' -d '{"name":"testteam","display_name":"Test Team"}'Affected if The API returns HTTP 200 or 201 success instead of HTTP 401 Unauthorized, indicating unauthenticated team creation is possible
The server is affected if it runs any Mattermost Server version below 3.6.3 with the API endpoint exposed to untrusted networks, allowing team creation without authentication.
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 data3.6.3
Upgrade Mattermost Server to version 3.7.0, 3.6.3, or later to patch the unauthenticated team creation vulnerability.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18919 — 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-2017-18919 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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