Cyber Resilience

CVE-2026-42903

Memory Safety in Microsoft Windows 10 21H2 ≤ 10.0.19044.7417

Published
09 June 2026
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0090 57th percentile
Risk Priority 52 floored blend · peak EPSS

Summary

CVE-2026-42903 is a medium-severity NULL Pointer Dereference (CWE-476) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 43% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV 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.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Null pointer dereference in Windows Kerberos allows an authorized attacker to deny service over a network.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
T1489 Service Stop Impact
Adversaries may stop or disable services on a system to render those services unavailable to legitimate users.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-59132Same product: Microsoft Windows 10 1607
CVE-2026-25165Same product: Microsoft Windows 10 1607
CVE-2026-40414Same product: Microsoft Windows 10 1607
CVE-2026-40401Same product: Microsoft Windows 10 1607
CVE-2026-40413Same product: Microsoft Windows 10 1607
CVE-2026-25168Same product: Microsoft Windows 10 1607
CVE-2026-57976Same product: Microsoft Windows 10 1607
CVE-2026-50366Same product: Microsoft Windows 10 1607
CVE-2026-34339Same product: Microsoft Windows 10 1607
CVE-2026-32071Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.9234 · ≤ 10.0.14393.9234
microsoft
windows 10 1809
≤ 10.0.17763.8880 · ≤ 10.0.17763.8880
microsoft
windows 10 21h2
≤ 10.0.19044.7417 · ≤ 10.0.19044.7417 · ≤ 10.0.19044.7417
microsoft
windows 10 22h2
≤ 10.0.19045.7417 · ≤ 10.0.19045.7417 · ≤ 10.0.19045.7417
microsoft
windows 11 23h2
≤ 10.0.22631.7219 · ≤ 10.0.22631.7219
microsoft
windows 11 24h2
≤ 10.0.26100.8655 · ≤ 10.0.26100.8655
microsoft
windows 11 25h2
≤ 10.0.26200.8655 · ≤ 10.0.26200.8655
microsoft
windows 11 26h1
≤ 10.0.28000.2269 · ≤ 10.0.28000.2269
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.9234
+3 more product configuration(s) — see NVD for full list

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.

PR.PS-06 mostly match
prevents

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.

finds

Security testing can detect NULL dereference defects before release.

prevents

Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.

prevents

Application security requirements can specify input validation and pointer-safety rules.

prevents

Secure architecture principles encourage defensive design that avoids unsafe pointer use.

prevents

Secure coding standards directly require NULL-pointer checks and safe dereference patterns.

References