Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-100223 Overview
An elevation of privilege vulnerability exists when reparse points are created by sandboxed processes allowing sandbox escape. An attacker who successfully exploited the vulnerability could use the sandbox escape to elevate privileges on an affected system. To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system. The security update addresses the vulnerability by preventing sandboxed processes from creating reparse points targeting inaccessible files.
Critical Impact
Affected Products
- Microsoft product: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-10: CVE-2026-100223 published to the National Vulnerability Database by secure@microsoft.com
- 2026-11-10: last updated in the NVD database
Technical Details for CVE-2026-100223
Vulnerability Analysis
CVE-2026-100223 is a Use After Free weakness (CWE-416: Use After Free) in Microsoft product. Based on its CVSS vector, the flaw needs local or adjacent access, needs some level of access, and needs no user interaction. Memory is used after it was released, which can lead to code execution.
With a CVSS base score of 7.8, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-416: Use After Free. Memory is used after it was released, which can lead to code execution.
Attack Vector
Based on the CVSS vector, the flaw needs local or adjacent access, needs some level of access, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Detection Methods for CVE-2026-100223
Detection Strategies
- Inventory every instance of Microsoft product and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward Microsoft product application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-100223
Immediate Actions Required
- Apply the fixed version of Microsoft product named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for Microsoft product.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
- CWE-416: Use After Free More CVEs with this weakness
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
Related CVEs
Access of resource using incompatible type ('type confusion') in Windows Shell allows an authorized attacker to elevate privileges locally.
Out-of-bounds read in Windows VMSwitch allows an authorized attacker to elevate privileges locally.
Null pointer dereference in Windows USM Communication Manager allows an authorized attacker to elevate privileges locally.
Use after free in Winsock allows an authorized attacker to elevate privileges locally.
Release of invalid pointer or reference in Windows Performance Monitor allows an unauthorized attacker to execute code over a network.
Use after free in Windows Credential User Interface allows an authorized attacker to elevate privileges locally.
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