CVE-2021-21565Network attack vector

DNS service interruption via SmartConnect error loop

Published Aug 2, 2021 · Updated Sep 16, 2024

Denial of service in SmartConnect in Dell PowerScale OneFS 9.1.0.3 and earlier allows remote attackers to interrupt DNS responses. When the error condition occurs, SmartConnect enters a CPU-consuming loop instead of recovering and continuing to process DNS requests. No authentication or user interaction is required; Dell has not disclosed the exact request that reaches the condition, and no data access or modification is reported.

CVSS severity5.3
Medium
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in SmartConnect in Dell PowerScale OneFS 9.1.0.3 and earlier allows remote attackers to interrupt DNS responses. When the error condition occurs, SmartConnect enters a CPU-consuming loop instead of recovering and continuing to process DNS requests. No authentication or user interaction is required; Dell has not disclosed the exact request that reaches the condition, and no data access or modification is reported.

The record

CVE
CVE-2021-21565
Published
Aug 2, 2021
Updated
Sep 16, 2024
Vendor
Dell Technologies
Product
PowerScale OneFS
Classifications
CWE-834, CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=9.1.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Dell Technologies · PowerScale OneFSversion=unspecified <=9.1.0.3

Published CVSS scores

5.3DellCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-834Excessive Iteration
CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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