CVE-2026-21525
Memory Safety in Microsoft Windows 10 21H2 ≤ 10.0.19044.6937
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-21525 is a medium-severity NULL Pointer Dereference (CWE-476) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 6.2 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 9% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-21525 is a null pointer dereference vulnerability (CWE-476) in the Windows Remote Access Connection Manager service. Published on 2026-02-10, it carries a CVSS v3.1 base score of 6.2 (AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and affects Windows systems running this component, enabling local denial of service.
An unauthorized attacker with local access to the target system can exploit the vulnerability with low attack complexity and no privileges or user interaction required. Exploitation triggers a null pointer dereference, resulting in a denial of service that causes high availability impact while leaving confidentiality and integrity unaffected.
Microsoft's update guide at msrc.microsoft.com provides patching details and advisories for remediation. Vicarius offers specific detection and mitigation scripts tailored to this DoS issue in the Remote Access Connection Manager. The vulnerability is also listed in CISA's Known Exploited Vulnerabilities catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-7329
Vulnerability Data
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
- CWE(s)
- KEV Date Added
- 10 February 2026
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including static analysis) directly finds null-dereference bugs before deployment.
Documented development standards and tools can enforce null-safety rules and safe pointer usage.
Engineering principles can mandate defensive coding such as explicit null checks before dereference.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect NULL dereference defects before release.
Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.
Application security requirements can specify input validation and pointer-safety rules.
Secure architecture principles encourage defensive design that avoids unsafe pointer use.
Secure coding standards directly require NULL-pointer checks and safe dereference patterns.