How severe is CVE-2021-42304?

CVE-2021-42304 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.

Is CVE-2021-42304 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42304?

CVE-2021-42304 affects Microsoft Azure Real Time Operating System. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42304?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-42304 published?

CVE-2021-42304 was published on 2021-11-10 and last updated on 2026-06-17.

CVE-2021-42304

CVE-2021-42304 is a medium-severity vulnerability in Microsoft Azure Real Time Operating System with a CVSS 3.x base score of 6.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-269.

Key facts

Severity: Medium (CVSS 3.x base score 6.6)
CVSS v2: 7.2
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-269
Affected product: Microsoft Azure Real Time Operating System
Published: 2021-11-10
Last modified: 2026-06-17

Description

Azure RTOS Elevation of Privilege Vulnerability

Frequently asked questions

What is CVE-2021-42304?: Azure RTOS Elevation of Privilege Vulnerability
How severe is CVE-2021-42304?: CVE-2021-42304 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability high.
Is CVE-2021-42304 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42304?: CVE-2021-42304 affects Microsoft Azure Real Time Operating System. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42304?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-42304 published?: CVE-2021-42304 was published on 2021-11-10 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42304

Affected products (1)

cpe:2.3:o:microsoft:azure_real_time_operating_system:*:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Azure Real Time Operating System

CVE-2021-42303 — Medium (CVSS 6.6): Azure RTOS Elevation of Privilege Vulnerability
CVE-2021-42302 — Medium (CVSS 6.6): Azure RTOS Elevation of Privilege Vulnerability
CVE-2021-42323 — Low (CVSS 3.3): Azure RTOS Information Disclosure Vulnerability
CVE-2021-26444 — Low (CVSS 3.3): Azure RTOS Information Disclosure Vulnerability

All CVEs affecting Microsoft Azure Real Time Operating System →

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