Cyber Resilience

CVE-2026-54990

Memory Safety in Microsoft Windows 11 24H2 ≤ 10.0.26100.8875

Published
14 July 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0054 43th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-54990 is a critical-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 11 24H2. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-16 (Memory Protection) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Heap-based buffer overflow in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
Why these techniques?

Heap buffer overflow in RDP client enables remote unauthenticated code execution, directly mapping to client-side exploitation technique.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-58542Same product: Microsoft Windows 11 24H2
CVE-2026-42993Same product: Microsoft Windows 11 24H2
CVE-2026-50679Same product: Microsoft Windows 11 24H2
CVE-2026-50327Same product: Microsoft Windows 11 24H2
CVE-2026-32223Same product: Microsoft Windows 11 24H2
CVE-2026-32221Same product: Microsoft Windows 11 24H2
CVE-2026-50655Same product: Microsoft Windows 11 24H2
CVE-2026-56189Same product: Microsoft Windows 11 24H2
CVE-2026-57090Same product: Microsoft Windows 11 24H2
CVE-2026-49796Same product: Microsoft Windows 11 24H2

Affected Assets

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 2025
≤ 10.0.26100.33158

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
  • SI-16 Memory Protection
  • SC-7 Boundary Protection
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires timely remediation of the heap buffer overflow flaw in the Remote Desktop Client before exploitation.

prevent

Provides memory protection mechanisms that can block or contain heap-based buffer overflows leading to code execution.

prevent

Boundary protection can restrict network traffic to the vulnerable Remote Desktop Client, reducing remote attack surface.

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 full match
prevents

Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.

PR.PS-02 partial match
prevents

Timely patching removes known heap-overflow instances after they exist.

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.

detects

Security testing in development and acceptance can detect heap overflows before release.

prevents

Secure development lifecycle mandates practices that reduce the likelihood of introducing heap overflows.

prevents

Application security requirements can specify bounds-checking and safe memory APIs that mitigate heap overflows.

prevents

Secure architecture and engineering principles include memory-safety and input-validation controls that address heap overflows.

prevents

Secure coding standards directly prescribe techniques (safe functions, bounds checks) that prevent heap-based buffer overflows.

none

Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.

References