Security readout for executives and security teams
Plain-English summary
Mattermost Server versions before 4.0.0, 3.10.2, and 3.9.2 may be exposed to cross-site request forgery when CORS is enabled. The public record does not describe the affected action or business impact, so urgency depends on whether older Mattermost deployments still exist and allow CORS.
Executive priority
Treat this as a configuration-dependent legacy risk. It is not KEV-listed in the supplied data, but older collaboration platforms can carry business impact if they remain internet-accessible. Confirm version and CORS status before assigning emergency priority.
Technical view
CVE-2017-18903 is described as a CSRF issue in Mattermost Server before 4.0.0, 3.10.2, and 3.9.2, conditional on CORS being enabled. The source bundle provides no CVSS score, CWE, affected CPEs, endpoint details, or patch notes beyond the version boundary.
Likely exposure
Exposure is most likely in self-hosted Mattermost Server instances older than 4.0.0, 3.10.2, or 3.9.2 where CORS was enabled. The source bundle does not identify hosted-service exposure, specific configurations, or affected endpoints.
Exploitation context
CISA KEV status is false in the supplied bundle, and no cited source states active exploitation. The public data only says CSRF can occur if CORS is enabled; it does not provide exploit availability, exploitation prerequisites, or observed attack activity.
Researcher notes
Evidence is thin: no CVSS, CWE, endpoint detail, exploit description, or CPE data is provided. The safest assessment is version-and-configuration scoping, followed by vendor guidance review. Avoid assuming impact beyond CSRF conditional on CORS being enabled.
Mitigation direction
- Upgrade Mattermost Server to a version not listed as affected by the CVE description.
- Disable CORS unless it is explicitly required for a documented integration.
- Restrict any required CORS configuration to trusted origins only.
- Review Mattermost security update guidance for version-specific remediation details.
- Prioritize unsupported or internet-accessible Mattermost deployments for replacement or upgrade.
Validation and detection
- Inventory all Mattermost Server instances and record their exact versions.
- Confirm whether CORS is enabled in Mattermost or surrounding proxy configuration.
- Verify production versions are 4.0.0, 3.10.2, 3.9.2, or later.
- Review vendor security updates for any environment-specific instructions.
- Check security monitoring for suspicious cross-origin browser-driven activity if older versions remain.
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-2017-18903 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.