How severe is CVE-2023-21805?

CVE-2023-21805 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-21805 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-21805?

CVE-2023-21805 primarily affects Microsoft Windows 10. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-21805?

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-2023-21805 published?

CVE-2023-21805 was published on 2023-02-14 and last updated on 2026-06-17.

CVE-2023-21805

CVE-2023-21805 is a high-severity vulnerability in Microsoft Windows 10 with a CVSS 3.x base score of 7.8. 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-77.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-77
Affected product: Microsoft Windows 10
Published: 2023-02-14
Last modified: 2026-06-17

Description

Windows MSHTML Platform Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2023-21805?: Windows MSHTML Platform Remote Code Execution Vulnerability
How severe is CVE-2023-21805?: CVE-2023-21805 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-21805 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-21805?: CVE-2023-21805 primarily affects Microsoft Windows 10. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-21805?: 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-2023-21805 published?: CVE-2023-21805 was published on 2023-02-14 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21805

Affected products (15)

cpe:2.3:o:microsoft:windows_10:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_21h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_22h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:*

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