Security readout for executives and security teams
Plain-English summary
Older Mattermost Server versions could expose user status information through a REST API v4 endpoint. The disclosed impact is information leakage, not system takeover. Business urgency depends on whether an organization still runs affected 4.0, 4.1, or pre-4.2 releases and exposes Mattermost APIs to untrusted users or networks.
Executive priority
Prioritize remediation if legacy Mattermost is still deployed or exposed externally. The known impact is limited information disclosure, but status data can support profiling or social engineering. Modern supported versions should reduce concern.
Technical view
CVE-2017-18895 affects Mattermost Server before 4.2.0, 4.1.1, and 4.0.5. The issue permits attackers to obtain sensitive user status data via a REST API version 4 endpoint. The provided sources do not include CVSS, CWE, authentication context, proof-of-concept details, or vendor workaround text.
Likely exposure
Exposure is most likely in legacy Mattermost Server deployments below 4.2.0, 4.1.1, or 4.0.5 where REST API v4 endpoints are reachable by untrusted parties.
Exploitation context
The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. Treat this as a legacy information disclosure issue unless internal telemetry or vendor guidance indicates otherwise.
Researcher notes
Evidence is sparse. The record identifies the affected version boundary and data type exposed, but not the precise endpoint, authentication requirements, CVSS score, CWE, exploit availability, or workaround. Avoid assuming unauthenticated access without vendor confirmation.
Mitigation direction
- Upgrade Mattermost Server to 4.2.0, 4.1.1, 4.0.5, or a later supported release.
- Review Mattermost security updates for any release-specific guidance.
- Restrict Mattermost API access to trusted networks where operationally feasible.
- Monitor for unusual REST API v4 access patterns involving user status data.
Validation and detection
- Inventory Mattermost Server versions across production and non-production environments.
- Confirm no deployed instance is below 4.2.0, 4.1.1, or 4.0.5.
- Review access logs for suspicious calls to REST API v4 status-related endpoints.
- Verify API exposure from internet, partner networks, and internal untrusted segments.
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-2017-18895 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.