Security readout for executives and security teams
Plain-English summary
CVE-2018-21248 affects Mattermost Server versions before 5.4.0. The public record says the server mishandled extra authentication credentials. Business risk is unclear because no CVSS score, CWE, detailed impact, or exploit evidence is provided in the supplied sources.
Executive priority
Treat this as a credential-handling risk with incomplete public detail. Prioritize confirming whether any Mattermost Server instance remains below 5.4.0, especially where external users or sensitive internal discussions are present.
Technical view
The CVE describes an authentication-credential handling flaw in Mattermost Server before 5.4.0. The phrase “superfluous authentication credentials” is not further explained in the supplied sources, so precise impact, attack preconditions, and affected configurations are not public here.
Likely exposure
Exposure is most likely limited to organizations running Mattermost Server versions earlier than 5.4.0. The provided affected-product metadata is incomplete, so validate using installed Mattermost version data rather than CPE matching alone.
Exploitation context
The source bundle does not show CISA KEV inclusion or any cited evidence of active exploitation. No exploit status should be assumed from the available information.
Researcher notes
The CVE record lacks CVSS, CWE, CPEs, and technical detail. Analysis should stay bounded to Mattermost Server before 5.4.0 and the stated credential-handling issue until vendor guidance provides more specificity.
Mitigation direction
- Identify any Mattermost Server deployments and record their exact versions.
- Move deployments running before 5.4.0 to a vendor-supported fixed release.
- Review Mattermost’s security updates page for any linked advisory details.
- Prioritize internet-facing or high-sensitivity collaboration environments first.
Validation and detection
- Check asset inventory for Mattermost Server instances older than 5.4.0.
- Confirm patch status from application version banners or administrative version records.
- Review authentication logs for unusual credential or session behavior.
- Document any unknown Mattermost instances for owner follow-up.
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-2018-21248 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.