Security readout for executives and security teams
Plain-English summary
Older Mattermost Server versions allowed outsiders to create teams through the API without authentication. For an exposed instance, this could let unauthorized users create workspaces and disrupt governance. The source bundle does not provide CVSS, detailed impact, or exploitation evidence.
Executive priority
Treat as a legacy exposure cleanup item with moderate urgency, higher if old Mattermost servers are internet-facing. Prioritize confirmation and upgrade because the flaw bypasses authentication for team creation.
Technical view
CVE-2017-18919 affects Mattermost Server before 3.7.0 and 3.6.3. The reported flaw is unauthenticated team creation through the API. Available sources do not name CWE, CVSS vector, detailed endpoint behavior, or exploit prerequisites beyond unauthenticated API access.
Likely exposure
Likely exposure is self-managed Mattermost Server deployments older than 3.7.0 or 3.6.3 with reachable API access. The bundle does not establish cloud exposure or affected configurations beyond the version statement.
Exploitation context
CISA KEV status is false in the bundle, and no cited source states active exploitation. The issue is still relevant for legacy Mattermost deployments because unauthenticated API behavior can be abused remotely when exposed.
Researcher notes
Evidence is sparse: the record identifies affected versions and impact, but lacks CVSS, CWE, endpoint details, and exploit telemetry. Avoid assuming broader compromise from this CVE alone; focus validation on version state and unexpected team creation.
Mitigation direction
- Upgrade Mattermost Server to 3.7.0, 3.6.3, or a later supported release.
- Review Mattermost security update guidance for version-specific upgrade notes.
- Restrict external access to legacy Mattermost APIs until upgraded.
- Audit existing teams for unauthorized or unexpected creations.
Validation and detection
- Inventory Mattermost Server versions across all environments.
- Confirm no instance remains below 3.7.0 or 3.6.3.
- Review server logs for unauthenticated team creation activity.
- Check Mattermost team lists for suspicious or unapproved teams.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2017-18919 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://mattermost.com/security-updates/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.