medium6.2Known exploited
CVE-2026-21525
Microsoft Windows NULL Pointer Dereference Vulnerability
Exploited in the wild
This vulnerability is on the CISA Known Exploited Vulnerabilities list, added 2026-02-10. Federal due date: 2026-03-03.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Impact
Microsoft Windows Remote Access Connection Manager contains a NULL pointer dereference that could allow an unauthorized attacker to deny service locally.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Microsoft | Windows 10 1607 | before 10.0.14393.8868 |
| Microsoft | Windows 10 1809 | before 10.0.17763.8389 |
| Microsoft | Windows 10 21h2 | before 10.0.19044.6937 |
| Microsoft | Windows 10 22h2 | before 10.0.19045.6937 |
| Microsoft | Windows 11 23h2 | before 10.0.22631.6649 |
| Microsoft | Windows 11 24h2 | before 10.0.26100.7781 |
| Microsoft | Windows 11 25h2 | before 10.0.26200.7781 |
| Microsoft | Windows Server 2012 | All versions Version r2 |
| Microsoft | Windows Server 2016 | before 10.0.14393.8868 |
| Microsoft | Windows Server 2019 | before 10.0.17763.8389 |
| Microsoft | Windows Server 2022 | before 10.0.20348.4711 |
| Microsoft | Windows Server 2022 23h2 | before 10.0.25398.2149 |
Weakness classification
References
- NVD record
- CVE.org record
- CISA KEV catalog
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525
- https://www.vicarius.io/vsociety/posts/cve-2026-21525-detection-script-dos-vulnerability-in-windows-remote-access-connection-manager
- https://www.vicarius.io/vsociety/posts/cve-2026-21525-mitigation-script-dos-vulnerability-in-windows-remote-access-connection-manager
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21525