Security readout for executives and security teams
Plain-English summary
Mattermost Server versions before 3.6.2 had a WebSocket same-origin policy issue. In business terms, a browser-based trust boundary may not have been enforced as expected. The available sources do not provide severity, CVSS, or impact detail, so urgency depends on whether affected Mattermost versions remain deployed.
Executive priority
Prioritize as an inventory and lifecycle issue unless affected versions are found. If Mattermost Server before 3.6.2 is still in use, schedule remediation promptly because the flaw affects a browser trust boundary.
Technical view
CVE-2017-18920 describes Mattermost Server before 3.6.2 with WebSocket functionality that did not follow the Same Origin Policy. The source bundle does not provide CVSS, CWE, affected CPEs, exploit details, or a detailed vendor advisory entry beyond the Mattermost security updates reference.
Likely exposure
Exposure is limited to organizations running Mattermost Server earlier than 3.6.2. The bundle does not identify editions, deployment modes, or CPEs, so confirm exposure through asset inventory and installed version checks.
Exploitation context
The provided sources do not state active exploitation, public exploitation, or inclusion in CISA KEV. Treat exploit status as unconfirmed. The issue concerns WebSocket origin enforcement, which is relevant when users access Mattermost through browsers.
Researcher notes
Evidence is sparse. The CVE text identifies only Mattermost Server before 3.6.2 and a WebSocket Same Origin Policy failure. No CVSS vector, CWE mapping, affected CPE, exploit status, or detailed impact statement is provided in the source bundle.
Mitigation direction
- Identify any Mattermost Server instances older than 3.6.2.
- Review Mattermost security updates for vendor-supported remediation guidance.
- Upgrade affected servers to a supported, non-affected Mattermost version.
- Limit access to legacy Mattermost instances until remediation is confirmed.
Validation and detection
- Confirm deployed Mattermost Server versions from trusted asset records.
- Verify no production instance reports a version earlier than 3.6.2.
- Review reverse proxy and application records for exposed Mattermost endpoints.
- Check vendor release notes for any additional configuration guidance.
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-2017-18920 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.