Microsoft Windows NULL Pointer Dereference Vulnerability
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
What happened
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
CISA lists it as exploited, added 10 Feb 2026.
Does it affect you
Names Microsoft Windows Server. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Follow the vendor advisory for the fixed release and any interim mitigation.
msrc.microsoft.com - Follow the vendor advisory for the fixed release and any interim mitigation.
vicarius.io - Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
cisa.gov
CISA’s notes for this entry:
Affected, as published to NVD
- ms-winserver
- Microsoft Windows Server: everything below 10.0.14393.8868
The record
- NVD status
- Analyzed
- Published
- 10 Feb 2026, last modified 17 Jun 2026 (NVD)
- Severity
- CVSS 3.1 base score 6.2, Medium — computed here from the vector; NVD states 6.2.
- Vector
- CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness
- CWE-476 NULL Pointer Dereference (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 10 Feb 2026; federal remediation due 03 Mar 2026. CISA entry
- Exploit probability
- EPSS 4.8%, 92nd percentile — FIRST, scored 23 Oct 2026. FIRST EPSS
- Vendor
- Microsoft · Windows (CISA)
References on the NVD record
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525Vendor Advisory
- vicarius.io/vsociety/posts/cve-2026-21525-mitigation-script-dos-vulnerability-in-windows-remote-access-connection-managerMitigationThird Party Advisory
- vicarius.io/vsociety/posts/cve-2026-21525-detection-script-dos-vulnerability-in-windows-remote-access-connection-managerThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21525US Government Resource
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.