Cyber Resilience

CVE-2026-49783

Microsoft Windows 10 21H2 ≤ 10.0.19044.7548

Published
14 July 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0026 17th percentile
Risk Priority 56 floored blend · peak EPSS

Summary

CVE-2026-49783 is a high-severity Improperly Implemented Security Check for Standard (CWE-358) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Downgrade Attack (T1689); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

Improperly implemented security check for standard in Windows Secure Boot allows an authorized attacker to bypass a security feature locally.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1689 Downgrade Attack Defense Impairment
Adversaries may downgrade or use a version of system features that may be outdated, vulnerable, and/or does not support updated security controls.
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-21267Same vendor: Microsoft
CVE-2024-49039Same product: Microsoft Windows 10 1607
CVE-2024-43646Same product: Microsoft Windows 10 1607
CVE-2023-32043Same product: Microsoft Windows 10 1607
CVE-2023-35332Same product: Microsoft Windows 10 1607
CVE-2025-21202Same product: Microsoft Windows 10 1607
CVE-2025-21219Same product: Microsoft Windows 10 1607
CVE-2024-49107Same product: Microsoft Windows 10 1607
CVE-2023-38140Same product: Microsoft Windows 10 1607
CVE-2025-21211Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.9339 · ≤ 10.0.14393.9339
microsoft
windows 10 1809
≤ 10.0.17763.9020 · ≤ 10.0.17763.9020
microsoft
windows 10 21h2
≤ 10.0.19044.7548 · ≤ 10.0.19044.7548 · ≤ 10.0.19044.7548
microsoft
windows 10 22h2
≤ 10.0.19045.7548 · ≤ 10.0.19045.7548 · ≤ 10.0.19045.7548
microsoft
windows 11 24h2
≤ 10.0.26100.8875 · ≤ 10.0.26100.8875
microsoft
windows 11 25h2
≤ 10.0.26200.8875 · ≤ 10.0.26200.8875
microsoft
windows 11 26h1
≤ 10.0.28000.2269 · ≤ 10.0.28000.2525
microsoft
windows server 2016
≤ 10.0.14393.9339
microsoft
windows server 2019
≤ 10.0.17763.9020
microsoft
windows server 2022
≤ 10.0.20348.5386
+1 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V17.2.8

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-358

Assessments identify and document improperly implemented security checks, allowing fixes that reduce exploitation of flawed checks.

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 directly require correct implementation of standardized security checks and algorithms.

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 in development and acceptance validates that required security checks function as specified.

prevents

Use of cryptography control depends on correct implementation of standardized cryptographic checks.

prevents

Secure development life cycle mandates verification that security checks required by standards are correctly implemented.

prevents

Application security requirements explicitly call for correct implementation of standardized security mechanisms.

prevents

Secure system architecture and engineering principles require faithful realization of protocol-level security checks.

prevents

Secure coding practices directly address correct implementation of security-relevant checks in standardized algorithms.

References