Security readout for executives and security teams
Plain-English summary
Mattermost Server before 5.13.0 had a restriction failure around creating incoming webhooks. In business terms, affected collaboration systems may have allowed webhook creation in situations Mattermost intended to block. The public bundle does not describe data theft, remote code execution, or confirmed exploitation.
Executive priority
Treat this as a targeted upgrade and configuration review item, not an emergency based on available evidence. Prioritize any older Mattermost systems used for sensitive internal communications or broad integrations.
Technical view
CVE-2019-20863 affects Mattermost Server before 5.13.0. The issue is that incoming webhook creation was not properly restricted. The provided sources do not include CVSS, CWE, CPEs, prerequisites, exploitability details, or a full impact statement beyond the authorization restriction failure.
Likely exposure
Exposure is limited to organizations running Mattermost Server versions before 5.13.0. The source bundle does not identify specific editions, configurations, CPEs, or whether internet exposure changes risk.
Exploitation context
CISA KEV status is false, and the supplied sources do not report active exploitation. No exploit method, public proof of concept, or attacker prerequisites are provided in the bundle.
Researcher notes
The public record is sparse. Analysis should avoid assuming unauthenticated access, privilege escalation scope, or downstream impact. Focus validation on version confirmation, webhook inventory, permissions, and any vendor details available from Mattermost security updates.
Mitigation direction
- Inventory Mattermost Server deployments and identify versions before 5.13.0.
- Review Mattermost security updates and vendor upgrade guidance.
- Upgrade affected Mattermost Server instances to 5.13.0 or later where supported.
- Review existing incoming webhooks and remove unapproved entries.
- Restrict webhook administration to trusted roles pending remediation.
Validation and detection
- Confirm each Mattermost Server version is 5.13.0 or later.
- Review integration settings for unexpected incoming webhooks.
- Check administrative audit logs for unusual webhook creation events.
- Verify role permissions around incoming webhook management.
- Document any affected instance that cannot be upgraded immediately.
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-2019-20863 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.