CVE DATABASE / CVE-2026-21525
CVE-2026-21525
Microsoft Windows NULL Pointer Dereference Vulnerability
CVSS 6.2 · MEDIUM
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2026-02-10.
Federal remediation due 2026-03-03.
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Summary
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
CVSS 3.1 breakdown
| Base score | 6.2 (MEDIUM) |
| Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Attack vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity | NONE |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Microsoft windows 10 1607Microsoft windows 10 1809Microsoft windows 10 21h2Microsoft windows 10 22h2Microsoft windows 11 23h2Microsoft windows 11 24h2Microsoft windows 11 25h2Microsoft windows server 2012Microsoft windows server 2016Microsoft windows server 2019Microsoft windows server 2022Microsoft windows server 2022 23h2Microsoft windows server 2025
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References
- 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
Data: NIST NVD + CISA KEV. NVD last modified 2026-03-30. Always verify against the vendor advisory before acting.