Security readout for executives and security teams
Plain-English summary
Dell PowerScale OneFS 9.1.0.3 and earlier has a SmartConnect DNS denial-of-service flaw. A network attacker could trigger an error loop that consumes CPU and may stop SmartConnect from answering other DNS requests. The impact is service availability, not data theft or data modification.
Executive priority
Treat as a scheduled operational-risk fix. Prioritize internet-exposed or broadly reachable SmartConnect DNS deployments, but available evidence does not support emergency handling for active exploitation.
Technical view
CVE-2021-21565 is CWE-400 resource consumption in SmartConnect on Dell PowerScale OneFS 9.1.0.3 and earlier. CVSS 3.1 is 5.3: network reachable, low complexity, no privileges, no user interaction, low availability impact, no confidentiality or integrity impact.
Likely exposure
Exposure is likely limited to Dell PowerScale OneFS deployments running version 9.1.0.3 or earlier with SmartConnect DNS reachable by untrusted or broad internal networks.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. The CVSS vector indicates unauthenticated network triggering is possible, but sources do not provide exploit maturity or observed attacks.
Researcher notes
The important technical signal is resource exhaustion: a SmartConnect error condition can loop and consume CPU, degrading DNS responses. Sources do not include exploit details, fixed version specifics, or compensating controls beyond Dell guidance.
Mitigation direction
- Check Dell advisory 000188148 for fixed OneFS releases or hotfix guidance.
- Remediate affected OneFS 9.1.0.3 and earlier systems per Dell guidance.
- Restrict SmartConnect DNS reachability to trusted networks where operationally possible.
- Monitor SmartConnect DNS health and CPU saturation until remediation is complete.
Validation and detection
- Inventory all Dell PowerScale clusters and record OneFS versions.
- Identify systems running OneFS 9.1.0.3 or earlier.
- Confirm whether SmartConnect DNS is reachable from untrusted networks.
- Verify remediation status against Dell advisory 000188148.
- Review monitoring for CPU spikes and SmartConnect DNS response failures.
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-400: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-21565 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
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.dell.com/support/kbdoc/000188148CVE 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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.