Security readout for executives and security teams
Plain-English summary
Dell Hybrid Client systems before version 1.5 have a flaw where a local, unauthenticated person could reach a protected function and potentially gain root-level control. This is serious for managed endpoint fleets, but the provided sources describe local access and high attack complexity, not internet-scale remote exploitation.
Executive priority
Treat as a high-priority endpoint remediation item where Dell Hybrid Client is deployed. It can lead to root-level access, but urgency should be weighted by local-access requirements, fleet size, and whether vulnerable versions remain in service.
Technical view
CVE-2021-21535 is CWE-306: missing authentication for a critical function in Dell Hybrid Client prior to 1.5. CVSS 3.1 is 7.4 with local attack vector, high complexity, no privileges or user interaction, unchanged scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Dell Hybrid Client deployments running versions before 1.5. The source bundle does not identify specific CPEs, configurations, or downstream distributions, so asset inventory is required to confirm scope.
Exploitation context
The CVE is not listed as CISA KEV in the provided bundle. No cited source states active exploitation or public exploit availability. The described attacker position is local and unauthenticated, with high attack complexity.
Researcher notes
The available evidence is concise: affected product, version boundary, CWE, CVSS vector, and Dell advisory reference. It does not provide implementation details, exploit primitives, or reliable indicators of compromise. Avoid assuming remote reachability or active exploitation.
Mitigation direction
- Inventory Dell Hybrid Client endpoints and record installed versions.
- Upgrade affected Dell Hybrid Client systems to version 1.5 or later per Dell guidance.
- Restrict physical and local access to affected endpoints until remediated.
- Review Dell advisory DSA-2021-071 for any environment-specific instructions.
Validation and detection
- Confirm no Dell Hybrid Client endpoint remains below version 1.5.
- Verify patch status against Dell advisory DSA-2021-071.
- Check endpoint management records for failed or deferred updates.
- Document exceptions with owner, compensating controls, and remediation date.
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-306: 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 lookupCVE-2021-21535 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
- High
- CVSS
- 7.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/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:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H1.45.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.dell.com/support/kbdoc/en-us/000184667/dsa-2021-071-dell-hybrid-client-security-update-for-multiple-vulnerabilitiesCVE 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.
Missing Authentication for Critical Function
Missing Authentication for Critical Function represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.