How severe is CVE-2023-21554?

CVE-2023-21554 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-21554 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 95% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-21554?

CVE-2023-21554 primarily affects Microsoft Windows 10 1607. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-21554?

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

When was CVE-2023-21554 published?

CVE-2023-21554 was published on 2023-04-11 and last updated on 2026-06-17.

CVE-2023-21554

CVE-2023-21554 is a critical-severity vulnerability in Microsoft Windows 10 1607 with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 95% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 95% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Microsoft Windows 10 1607
Published: 2023-04-11
Last modified: 2026-06-17

Description

Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability

Frequently asked questions

What is CVE-2023-21554?: Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
How severe is CVE-2023-21554?: CVE-2023-21554 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-21554 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 95% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-21554?: CVE-2023-21554 primarily affects Microsoft Windows 10 1607. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-21554?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2023-21554 published?: CVE-2023-21554 was published on 2023-04-11 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21554

Affected products (14)

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:-:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Windows 10 1607

CVE-2026-47291 — Critical (CVSS 9.8): Integer overflow or wraparound in Windows HTTP.sys allows an unauthorized attacker to execute code over a network.
CVE-2026-44815 — Critical (CVSS 9.8): Stack-based buffer overflow in Windows DHCP Client allows an unauthorized attacker to execute code over a network.
CVE-2026-33824 — Critical (CVSS 9.8): Double free in Windows IKE Extension allows an unauthorized attacker to execute code over a network.
CVE-2025-60724 — Critical (CVSS 9.8): Heap-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a…
CVE-2025-53766 — Critical (CVSS 9.8): Heap-based buffer overflow in Windows GDI+ allows an unauthorized attacker to execute code over a network.
CVE-2025-47981 — Critical (CVSS 9.8): Heap-based buffer overflow in Windows SPNEGO Extended Negotiation allows an unauthorized attacker to execute code over…

All CVEs affecting Microsoft Windows 10 1607 →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →