How severe is CVE-2021-43889?

CVE-2021-43889 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43889 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43889?

CVE-2021-43889 affects Microsoft Defender For Iot. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43889?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-43889 published?

CVE-2021-43889 was published on 2021-12-15 and last updated on 2026-06-17.

CVE-2021-43889

CVE-2021-43889 is a high-severity vulnerability in Microsoft Defender For Iot with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 6.5
EPSS exploit prediction: 2% (80th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Defender For Iot
Published: 2021-12-15
Last modified: 2026-06-17

Description

Microsoft Defender for IoT Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2021-43889?: Microsoft Defender for IoT Remote Code Execution Vulnerability
How severe is CVE-2021-43889?: CVE-2021-43889 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43889 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43889?: CVE-2021-43889 affects Microsoft Defender For Iot. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43889?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-43889 published?: CVE-2021-43889 was published on 2021-12-15 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43889

Affected products (1)

cpe:2.3:a:microsoft:defender_for_iot:*:*:*:*:*:*:*:*

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