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

Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-03-03 as the remediation due date.

Patch available

What, why and how

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

What

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

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-02-10.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: local access → NULL Pointer Dereference → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Local
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-476 ↗
CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.

UnauthenticatedCWE-476CISA KEV

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-7329Known-exploited evidence recorded

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

Official EUVD record ↗

BSI · German · WID-SEC-2026-0369Microsoft Windows: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Windows-Produkten ausnutzen, um Administratorrechte zu erlangen, beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Spoofing-Angriffe zu starten, Daten zu manipulieren, vertrauliche Informationen offenzulegen und einen Denial-of-Service-Zustand zu verursachen.

Official advisory ↗

Canadian Centre for Cyber Security · English · AV26-111Microsoft security advisory – February 2026 monthly rollup (AV26-111) - Update 1

On February 10, 2026, Microsoft published security advisories to address vulnerabilities in multiple products. Included were critical updates for the following products: Microsoft has received reports that CVE-2026-21525, CVE-2026-21514, CVE-2026-21510, CVE-2026-21513, CVE-2026-21533 and CVE-2026-21519 are being exploited.

Official advisory ↗

Cyber Security Agency of Singapore · English · CSA-SB-20260211Security Bulletin 11 Feb 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 11 Feb 2026, published on 11 February 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗

CERT-FR · French · CERTFR-2026-AVI-0150Multiples vulnérabilités dans Microsoft Windows

6-21250 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21251 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21253 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21255 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21508 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21510 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21513 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21517 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21519 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21525 du 10 février 2026 Bulletin de sécurité Microsoft Windows CVE-2026-21533 du 10 février 2026 Une gestion de version détaillée se trouve à la fin de ce document. Risques Atteinte à la confidentialité des données Contournement de la politique de sécurité Déni de service à distance Exécution de code arbitraire à distance Élévation de privilèges Systèmes affectés .NET 10.0 installed sur Windows versions antérieures à 10.0.3 .NET 8.0 installed sur Windows versions antérieures à 8.0.24 .NET 9.0 installed sur Windows versions antérieures à 9.0.13 Windows 10 Version 1607 pour systèmes 32 bits versions antérieures à 10.0.14393.8868 Windows 10 Version

Official advisory ↗

NBSZ-NKI · Hungarian · cve-2026-21525CVE-2026-21525

Közepes

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2026-003523マイクロソフトのMicrosoft Windows 10 1607等の複数製品におけるNULL ポインタデリファレンスに関する脆弱性

Windowsリモートアクセス接続マネージャにおけるヌルポインタ参照の脆弱性により、認証されていない攻撃者がローカルでサービス拒否攻撃を引き起こす可能性があります。

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2026-009406日立ディスクアレイシステムにおけるSVP 脆弱性対策について　(2026年2月分)

Microsoft製品に対して、以下に示す脆弱性が公開されました。 [脆弱性の内容] GDI+ サービス拒否の脆弱性 (CVE-2026-20846) Windows カーネルの情報漏えいの脆弱性 (CVE-2026-21222) Windows カーネルの特権の昇格の脆弱性 (CVE-2026-21231) Windows Connected Devices Platform Service に存在する特権昇格の脆弱性 (CVE-2026-21234) Windows Graphics コンポーネントの特権の昇格の脆弱性 (CVE-2026-21235) WinSock 用 Windows Ancillary Function Driver の特権の昇格の脆弱性 (CVE-2026-21236) Windows Subsystem for Linux の特権の昇格の脆弱性 (CVE-2026-21237) WinSock 用 Windows Ancillary Function Driver の特権の昇格の脆弱性 (CVE-2026-21238) Windows カーネルの特権の昇格の脆弱性 (CVE-2026-21239) Windows HTTP.sys の特権の昇格の脆弱性 (CVE-2026-21240) Windows Subsystem for Linux の特権の昇格の脆弱性 (CVE-2026-21242) Windows Hyper-V のリモートでコードが実行される脆弱性 (CVE-2026-21244) Windows Graphics コンポーネントの特権の昇格の脆弱性 (CVE-2026-21246) Windows Hyper-V のリモートでコードが実行される脆弱性 (CVE-2026-21247) Windows Hyper-V のリモートでコードが実行される脆弱性 (CVE-2026-21248) Windows NTLM のなりすましの脆弱性 (CVE-2026-21249) メールスロットファイルシステムの特権昇格の脆弱性 (CVE-2026-21253) Windows Hyper-V のセキュリティ機能のバイパスの脆弱性 (CVE-2026-21255) Windows ストレージの特権の昇格の脆弱性 (CVE-2026-21508) Windows シェルセキュリティ機能のバイパスの脆弱性 (CVE-2026-21510) MSHTML Framework Security Feature Bypass Vulnerability (CVE-2026-21513) デスクトップウィンドウマネージャーの特権の昇格の脆弱性 (CVE-2026-21519) Windows リモートアクセス接続マネージャーのサービス拒否の脆弱性 (CVE-2026-21525) Windows リモートデスクトップサービスの特権昇格の脆弱性 (CVE-2026-21533) SVPは直接ストレージ機能には係わりませんので、万一攻撃者から攻撃された場合であってもストレージとしてのデータの内容およびRead/Write機能に支障はありません。また日立ディスクアレイシステムに蓄積されているデータを読み取られることもありません。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-6688MS 2월 보안 위협에 따른 정기 보안 업데이트 권고

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-6686美 CISA 발표 주요 Exploit 정보공유(Update. 2026-02-10)

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

Official advisory ↗

NCSC-NL · Dutch · NCSC-2026-0053Kwetsbaarheden verholpen in Microsoft Windows

Een kwaadwillende kan de kwetsbaarheden misbruiken om aanvallen uit te voeren die kunnen leiden tot de volgende categorieën schade: - Denial-of-Service (DoS) - Manipulatie van gegevens - Toegang tot gevoelige gegevens - Uitvoeren van willekeurige code (gebruikersrechten) - Verkrijgen van verhoogde rechten - Omzeilen van een beveiligingsmaatregel - Spoofing ``` Desktop Window Manager: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21519 | 7.80 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Mailslot File System: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21253 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows LDAP - Lightweight Directory Access Protocol: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21243 | 7.50 | Denial-of-Service | |----------------|------|-------------------------------------| Windows Kernel: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21245 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21239 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21231 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21222 | 5.50 | Toegang tot gevoelige gegevens | |----------------|------|-------------------------------------| Windows Remote Desktop: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21533 | 7.80 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows Remote Access Connection Manager: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21525 | 6.20 | Denial-of-Service | |----------------|------|-------------------------------------| Windows Shell: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21510 | 8.80 | Omzeilen van beveiligingsmaatregel | |----------------|------|-------------------------------------| Role: Windows Hyper-V: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21248 | 7.30 | Uitvoeren van willekeurige code | | CVE-2026-21247 | 7.30 | Uitvoeren van willekeurige code | | CVE-2026-21255 | 8.80 | Omzeilen van beveiligingsmaatregel | | CVE-2026-21244 | 7.30 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Windows Win32K - GRFX: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2023-2804 | 6.50 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Windows Cluster Client Failover: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21251 | 7.80 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows HTTP.sys: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21250 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21240 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21232 | 7.80 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows Connected Devices Platform Service: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21234 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows GDI+: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-20846 | 7.50 | Denial-of-Service | |----------------|------|-------------------------------------| Windows App for Mac: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21517 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows NTLM: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21249 | 3.30 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| Windows Ancillary Function Driver for WinSock: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21236 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21241 | 7.00 | Verkrijgen van verhoogde rechten | | CVE-2026-21238 | 7.80 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Internet Explorer: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21513 | 8.80 | Omzeilen van beveiligingsmaatregel | |----------------|------|-------------------------------------| Windows Storage: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21508 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Windows Subsystem for Linux: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21242 | 7.00 | Verkrijgen van verhoogde rechten | | CVE-2026-21237 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| Microsoft Graphics Component: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-21246 | 7.80 | Verkrijgen van verhoogde rechten | | CVE-2026-21235 | 7.30 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| ```

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.8868
Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.8389
Windows 10 Version 21H2: 10.0.19044.0 < 10.0.19044.6937
Windows 10 Version 22H2: 10.0.19045.0 < 10.0.19045.6937
Windows 11 version 22H3: 10.0.22631.0 < 10.0.22631.6649
Windows 11 Version 23H2: 10.0.22631.0 < 10.0.22631.6649
Windows 11 Version 24H2: 10.0.26100.0 < 10.0.26100.7840
Windows 11 Version 25H2: 10.0.26200.0 < 10.0.26200.7840
Windows 11 version 26H1: 10.0.28000.0 < 10.0.28000.1575
Windows 11 Version 26H1: 10.0.28000.0 < 10.0.28000.1575
Windows Server 2012: 6.2.9200.0 < 6.2.9200.25923
Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.25923
Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.23022
Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.23022
Windows Server 2016: 10.0.14393.0 < 10.0.14393.8868
Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.8868
Windows Server 2019: 10.0.17763.0 < 10.0.17763.8389
Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.8389
Windows Server 2022: 10.0.20348.0 < 10.0.20348.4773
Windows Server 2022, 23H2 Edition (Server Core installation): 10.0.25398.0 < 10.0.25398.2149
Windows Server 2025: 10.0.26100.0 < 10.0.26100.32370
Windows Server 2025 (Server Core installation): 10.0.26100.0 < 10.0.26100.32370
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.

Evidence and provenance

Published 10 Feb 2026 · Last source change 19 Aug 2026, 16:26 UTC · CWE-476 · NULL Pointer Dereference

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2026-7329

Product sourceCISA KEV

Remediation sourceCVE/CNA references

CWE sourceOther authority

NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

1 Sep 2026, 08:57 UTC
BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
Before
no BlackTree article
After
1 BlackTree article
BlackTree editorial ↗
19 Aug 2026, 16:26 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
10.0.14393.0 < 10.0.14393.8868; 10.0.17763.0 < 10.0.17763.8389; 10.0.19044.0 < 10.0.19044.6937; 10.0.19045.0 < 10.0.19045.6937; 10.0.22631.0 < 10.0.22631.6649; 10.0.26100.0 < 10.0.26100.7840; 10.0.26200.0 < 10.0.26200.7840 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.8868; Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.8389; Windows 10 Version 21H2: 10.0.19044.0 < 10.0.19044.6937; Windows 10 Version 22H2: 10.0.19045.0 < 10.0.19045.6937; Windows 11 version 22H3: 10.0.22631.0 < 10.0.22631.6649; Windows 11 Version 23H2: 10.0.22631.0 < 10.0.22631.6649; Windows 11 Version 24H2: 10.0.26100.0 < 10.0.26100.7840; Windows 11 Version 25H2: 10.0.26200.0 < 10.0.26200.7840; Windows 11 version 26H1: 10.0.28000.0 < 10.0.28000.1575; Windows 11 Version 26H1: 10.0.28000.0 < 10.0.28000.1575; Windows Server 2012: 6.2.9200.0 < 6.2.9200.25923; Windows Server 2012 (Server Core installation): 6.2.9200.0 < 6.2.9200.25923; Windows Server 2012 R2: 6.3.9600.0 < 6.3.9600.23022; Windows Server 2012 R2 (Server Core installation): 6.3.9600.0 < 6.3.9600.23022; Windows Server 2016: 10.0.14393.0 < 10.0.14393.8868; Windows Server 2016 (Server Core installation): 10.0.14393.0 < 10.0.14393.8868; Windows Server 2019: 10.0.17763.0 < 10.0.17763.8389; Windows Server 2019 (Server Core installation): 10.0.17763.0 < 10.0.17763.8389; Windows Server 2022: 10.0.20348.0 < 10.0.20348.4773; Windows Server 2022, 23H2 Edition (Server Core installation): 10.0.25398.0 < 10.0.25398.2149; Windows Server 2025: 10.0.26100.0 < 10.0.26100.32370; Windows Server 2025 (Server Core installation): 10.0.26100.0 < 10.0.26100.32370 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
CNA ↗

2026-02-10CVE published

2026-02-10Added to CISA KEV

2026-08-19Mitigation reference recorded

ENISA EUVD · EUVD-2026-7329↗CISA KEV record↗CVE authority or vendor reference↗Mitigation reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Microsoft Windows NULL Pointer Dereference Vulnerability

Published severity in operational context

Evidence used

Compensating controls

Verification

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2026-7329

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication