Security readout for executives and security teams
Plain-English summary
CVE-2021-40390 is a critical authentication bypass in the Moxa MXView Series web application. If an organization runs MXView 3.2.4, an unauthenticated network attacker may gain unauthorized access, potentially affecting confidentiality, integrity, and availability of the management platform.
Executive priority
Prioritize this as urgent if MXView 3.2.4 exists in the environment. The issue is unauthenticated, network-reachable, and rated CVSS 10.0, but exploitation in the wild is not confirmed by the provided sources.
Technical view
The provided CVE data describes an unauthenticated, network-reachable authentication bypass in Moxa MXView Series 3.2.4 web application functionality. CVSS 3.0 is 10.0 with low complexity, no privileges, no user interaction, scope changed, and high impact across confidentiality, integrity, and availability. CWE-798 is listed.
Likely exposure
Exposure is limited to Moxa MXView Series version 3.2.4 based on the provided bundle. Risk is highest where the MXView web application is reachable from untrusted networks or the internet.
Exploitation context
The source bundle says a specially crafted HTTP request can trigger unauthorized access. It does not show CISA KEV listing or provide evidence of active exploitation. Treat exploit status as unconfirmed from these sources.
Researcher notes
The public bundle identifies affected product/version and impact but provides limited remediation detail. Avoid assuming broader MXView versions are affected unless vendor advisories confirm it. Focus validation on version discovery, management-plane exposure, and vendor advisory tracking.
Mitigation direction
- Identify any Moxa MXView Series 3.2.4 deployments immediately.
- Check Moxa and Talos guidance for fixed versions or vendor-approved mitigations.
- Restrict MXView web access to trusted administrative networks only.
- Remove internet exposure for the MXView management interface.
- Increase monitoring for unauthorized web application access attempts.
Validation and detection
- Inventory MXView assets and confirm exact installed versions.
- Verify whether MXView web interfaces are reachable from untrusted networks.
- Review access logs for unauthenticated or unusual web activity.
- Confirm remediation status against current Moxa or Talos advisory 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.
CWE-798: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-40390 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
- Critical
- CVSS
- 10 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
10CriticalVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1401CVE reference · x_refsource_MISC
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.
Use of Hard-coded Credentials
Use of Hard-coded Credentials represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.