Cyber Resilience

CVE-2023-21554

Critical

Published: 11 April 2023

Published
11 April 2023
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.9190 99.7th percentile
Risk Priority 75 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-21554 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

Microsoft Message Queuing (MSMQ) contains a remote code execution vulnerability tracked as CVE-2023-21554 and assigned a CVSS v3.1 score of 9.8. The flaw is rooted in improper input validation (CWE-20) within the MSMQ service and affects Microsoft Windows systems that have the Message Queuing feature enabled.

An unauthenticated attacker can send specially crafted network packets to an exposed MSMQ endpoint, resulting in arbitrary code execution with the privileges of the service account. Successful exploitation grants full confidentiality, integrity, and availability impact without requiring user interaction.

Microsoft has published remediation guidance and security updates for the vulnerability through its Security Response Center at the referenced URLs. Organizations should apply the vendor-supplied patches according to the instructions provided in those advisories.

The associated EPSS score currently stands at 0.9190 with a recorded peak of 0.9216, reflecting sustained high exploitation likelihood since disclosure.

EU & UK References

Vulnerability details

Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.5850
microsoft
windows 10 1809
≤ 10.0.17763.4252
microsoft
windows 10 20h2
≤ 10.0.19042.2846
microsoft
windows 10 21h2
≤ 10.0.19044.2846
microsoft
windows 10 22h2
≤ 10.0.19045.2846
microsoft
windows 11 21h2
≤ 10.0.22000.1817
microsoft
windows 11 22h2
≤ 10.0.22621.1555
microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
all versions
+2 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

References