# CVE-2026-21525

Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.

- Page: https://www.vulneraibility.com/cve/CVE-2026-21525
- CVSS: 6.2
- Known exploited: yes, in CISA KEV since 2026-02-10; CISA due date 2026-03-03
- EPSS: 4.87%
- CISA SSVC: exploitation active, automatable no, technical impact partial (assessed 2026-02-11)
- Weakness: CWE-476
- Published: 2026-02-10

## Affected versions

- Microsoft Windows 10 Version 1607: affected >= 10.0.14393.0 and < 10.0.14393.8868
- Microsoft Windows 10 Version 1809: affected >= 10.0.17763.0 and < 10.0.17763.8389
- Microsoft Windows 10 Version 21H2: affected >= 10.0.19044.0 and < 10.0.19044.6937
- Microsoft Windows 10 Version 22H2: affected >= 10.0.19045.0 and < 10.0.19045.6937
- Microsoft Windows 11 version 22H3: affected >= 10.0.22631.0 and < 10.0.22631.6649
- Microsoft Windows 11 Version 23H2: affected >= 10.0.22631.0 and < 10.0.22631.6649
- Microsoft Windows 11 Version 24H2: affected >= 10.0.26100.0 and < 10.0.26100.7840
- Microsoft Windows 11 Version 25H2: affected >= 10.0.26200.0 and < 10.0.26200.7840
- Microsoft Windows 11 version 26H1: affected >= 10.0.28000.0 and < 10.0.28000.1575
- Microsoft Windows 11 Version 26H1: affected >= 10.0.28000.0 and < 10.0.28000.1575
- Microsoft Windows Server 2012: affected >= 6.2.9200.0 and < 6.2.9200.25923
- Microsoft Windows Server 2012 R2: affected >= 6.3.9600.0 and < 6.3.9600.23022
- Microsoft Windows Server 2012 R2 (Server Core installation): affected >= 6.3.9600.0 and < 6.3.9600.23022
- Microsoft Windows Server 2012 (Server Core installation): affected >= 6.2.9200.0 and < 6.2.9200.25923
- Microsoft Windows Server 2016: affected >= 10.0.14393.0 and < 10.0.14393.8868
- Microsoft Windows Server 2016 (Server Core installation): affected >= 10.0.14393.0 and < 10.0.14393.8868
- Microsoft Windows Server 2019: affected >= 10.0.17763.0 and < 10.0.17763.8389
- Microsoft Windows Server 2019 (Server Core installation): affected >= 10.0.17763.0 and < 10.0.17763.8389
- Microsoft Windows Server 2022: affected >= 10.0.20348.0 and < 10.0.20348.4773
- Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): affected >= 10.0.25398.0 and < 10.0.25398.2149
- Microsoft Windows Server 2025: affected >= 10.0.26100.0 and < 10.0.26100.32370
- Microsoft Windows Server 2025 (Server Core installation): affected >= 10.0.26100.0 and < 10.0.26100.32370

A version outside these ranges is not a statement that it is unaffected.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21525
- [other] https://www.vicarius.io/vsociety/posts/cve-2026-21525-detection-script-dos-vulnerability-in-windows-remote-access-connection-manager
- [other] https://www.vicarius.io/vsociety/posts/cve-2026-21525-mitigation-script-dos-vulnerability-in-windows-remote-access-connection-manager

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.