CVE-2023-21555

CVE-2023-21555 is a high-severity vulnerability in Microsoft Windows 10 1607 with a CVSS 3.x base score of 8.1. 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-367.

Key facts

• Severity: High (CVSS 3.x base score 8.1)
• EPSS exploit prediction: 1% (65th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-367
• Affected product: Microsoft Windows 10 1607
• Published: 2023-01-10
• Last modified: 2026-06-17

Description

Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2023-21555?

Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability

How severe is CVE-2023-21555?

CVE-2023-21555 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-21555 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-21555?

CVE-2023-21555 primarily affects Microsoft Windows 10 1607. In total, 31 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-21555?

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-2023-21555 published?

CVE-2023-21555 was published on 2023-01-10 and last updated on 2026-06-17.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21555

Affected products (31)

• cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10_1607:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10_1809:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10_20h2:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10_21h2:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_10_22h2:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_11_21h2:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_11_21h2:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_11_22h2:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:x86:*
• cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_server_2008:-:sp2:*:*:*:*:x86:*
• 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:-:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Windows 10 1607

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All CVEs affecting Microsoft Windows 10 1607 →

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