CVE-2023-21554 — Windows 10 20h2
CRITICALCVE-2023-21554 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability in microsoft windows 10 20h2. 7 public exploit references exist, so weaponization risk is real. A fix is available — see the affected versions and patch details below.
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-21554.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-21554 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Affected Products
windows 10 20h2microsoftwindows 10 21h2microsoftwindows 10 22h2microsoftwindows 10 1607microsoftwindows 10 1809microsoftwindows 11 21h2microsoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Microsoft Message Queuing (MSMQ) Remote Code Execution Vulnerability
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every microsoft windows 10 20h2 deployment and check each version against the affected-products list above.
Fix
Apply the microsoft windows 10 20h2 security patch or hotfix for CVE-2023-21554 on the affected version, following the vendor advisory for your exact build.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2023-21554 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.