CVE-2026-21525: Microsoft Windows NULL Pointer Dereference Vulnerability

Published Feb 10, 2026
·
Updated

Microsoft Windows Remote Access Connection Manager contains a NULL pointer dereference that could allow an unauthorized attacker to deny service locally.

Other sources

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

Microsoft

Windows Remote Access Connection Manager Denial of Service Vulnerability

Microsoft

Affected Software

86 affected componentsFixes available
Microsoft Windows
Microsoft Windows 11=26H1
Microsoft Windows Server 2012 R2
Microsoft Windows 11=26H1
Microsoft Windows Server 2016
Microsoft Windows Server 2012
Microsoft Windows Server 2016
Microsoft Windows Server 2012 R2
Microsoft Windows 10=1607
Microsoft Windows 11=24H2
Microsoft Windows Server 2022, 23H2 Edition
Microsoft Windows 10=1607
Microsoft Windows Server 2025
Microsoft Windows Server 2012
Microsoft Windows 11=24H2
Microsoft Windows 11=25H2
Microsoft Windows 11=23H2
Microsoft Windows Server 2025
Microsoft Windows 11=23H2
Microsoft Windows 11=25H2
Microsoft Windows 10=22H2
Microsoft Windows 10=21H2
Microsoft Windows 10=22H2
Microsoft Windows Server 2022
Microsoft Windows 10=21H2
Microsoft Windows 10=22H2
Microsoft Windows Server 2019
Microsoft Windows 10=21H2
Microsoft Windows Server 2022
Microsoft Windows Server 2019
Microsoft Windows 10=1809
Microsoft Windows 10=1809
Microsoft Windows 10 1607<10.0.14393.8868
Microsoft Windows 10 1607<10.0.14393.8868
Microsoft Windows 10 1809<10.0.17763.8389
Microsoft Windows 10 1809<10.0.17763.8389
Microsoft Windows 10 21h2<10.0.19044.6937
Microsoft Windows 10 21h2<10.0.19044.6937
Microsoft Windows 10 21h2<10.0.19044.6937
Microsoft Windows 10 22h2<10.0.19045.6937
Microsoft Windows 10 22h2<10.0.19045.6937
Microsoft Windows 10 22h2<10.0.19045.6937
Microsoft Windows 11 23h2<10.0.22631.6649
Microsoft Windows 11 23h2<10.0.22631.6649
Microsoft Windows 11 24h2<10.0.26100.7781
Microsoft Windows 11 24h2<10.0.26100.7781
Microsoft Windows 11 25h2<10.0.26200.7781
Microsoft Windows 11 25h2<10.0.26200.7781
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016<10.0.14393.8868
Microsoft Windows Server 2019<10.0.17763.8389
Microsoft Windows Server 2022<10.0.20348.4711
Microsoft Windows Server 2022 23h2<10.0.25398.2149
Microsoft Windows Server 2025<10.0.26100.32313
Microsoft Windows 11=26H1
10.0.28000.1575
Microsoft Windows Server 2012 R2<6.3.9600.23022
6.3.9600.23022
Microsoft Windows Server 2016<10.0.14393.8868
10.0.14393.8868
Microsoft Windows Server 2012<6.2.9200.25923
6.2.9200.25923
Microsoft Windows Server 2016<10.0.14393.8868
10.0.14393.8868
Microsoft Windows 10=1607
10.0.14393.8868
Microsoft Windows Server 2012<6.2.9200.25923
6.2.9200.25923
Microsoft Windows Server 2025<10.0.26100.32370, <10.0.26100.32313
10.0.26100.3237010.0.26100.32313
Microsoft Windows Server 2012 R2<6.3.9600.23022
6.3.9600.23022
Microsoft Windows 10=1607
10.0.14393.8868
Microsoft Windows 11=24H2
10.0.26100.784010.0.26100.7781
Microsoft Windows 11=24H2
10.0.26100.784010.0.26100.7781
Microsoft Windows 11=26H1
10.0.28000.1575
Microsoft Windows 11=23H2
10.0.22631.6649
Microsoft Windows 11=25H2
10.0.26200.784010.0.26200.7781
Microsoft Windows Server 2022, 23H2 Edition<10.0.25398.2149
10.0.25398.2149
Microsoft Windows 11=25H2
10.0.26200.784010.0.26200.7781
Microsoft Windows 10=22H2
10.0.19045.6937
Microsoft Windows 10=21H2
10.0.19044.6937
Microsoft Windows 10=21H2
10.0.19044.6937
Microsoft Windows 11=23H2
10.0.22631.6649
Microsoft Windows Server 2022<10.0.20348.4773, <10.0.20348.4711
10.0.20348.477310.0.20348.4711
Microsoft Windows 10=21H2
10.0.19044.6937
Microsoft Windows Server 2022<10.0.20348.4773, <10.0.20348.4711
10.0.20348.477310.0.20348.4711
Microsoft Windows Server 2019<10.0.17763.8389
10.0.17763.8389
Microsoft Windows 10=1809
10.0.17763.8389
Microsoft Windows Server 2019<10.0.17763.8389
10.0.17763.8389
Microsoft Windows 10=22H2
10.0.19045.6937
Microsoft Windows 10=1809
10.0.17763.8389
Microsoft Windows Server 2025<10.0.26100.32370, <10.0.26100.32313
10.0.26100.3237010.0.26100.32313
Microsoft Windows 10=22H2
10.0.19045.6937

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.28000.1575Patch KB5077179
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.3.9600.23022Patch KB5075970
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.14393.8868Patch KB5075999
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.2.9200.25923Patch KB5075971
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.32370Fixed in 10.0.26100.32313Patch KB5075942
  6. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.7840Fixed in 10.0.26100.7781Patch KB5077212
  7. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.22631.6649Patch KB5075941
  8. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26200.7840Fixed in 10.0.26200.7781Patch KB5077212
  9. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.25398.2149Patch KB5075897
  10. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19045.6937Patch KB5075912
  11. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19044.6937Patch KB5075912
  12. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.20348.4773Fixed in 10.0.20348.4711Patch KB5075943
  13. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.17763.8389Patch KB5075904

Event History

Feb 10, 2026
CVE Published
via CISA·12:00 AM
Known Exploited
via CISA·12:00 AM
Data Sourced
via CISA·12:00 AM
RemedyDescriptionAffected Software
Data Sourced
via Microsoft·04:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·04:00 PM
Affected Software
Updated
via Microsoft·04:00 PM
Description
CVE Published
via MITRE·05:51 PM
Data Sourced
via MITRE·05:51 PM
DescriptionSeverity
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software
News Published
via The Register·10:10 PM
News Published
via The Register·10:13 PM
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Frequently Asked Questions

1

What is the severity of CVE-2026-21525?

CVE-2026-21525 has a severity rating that indicates it can lead to a denial of service attack.

2

How do I fix CVE-2026-21525?

To fix CVE-2026-21525, it is essential to apply the appropriate security patches from Microsoft based on your affected software version.

3

Which versions of Windows are affected by CVE-2026-21525?

CVE-2026-21525 affects various versions of Microsoft Windows, including Windows 10, Windows 11, and Windows Server editions.

4

What type of vulnerability is CVE-2026-21525?

CVE-2026-21525 is classified as a NULL pointer dereference vulnerability.

5

Can CVE-2026-21525 be exploited remotely?

CVE-2026-21525 is categorized as a local denial of service vulnerability, meaning it cannot be exploited remotely.

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