What is CVE-2026-54990?

CVE-2026-54990 is a critical-severity vulnerability in Microsoft Windows 11 Version 24h2, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-07-14.

How severe is CVE-2026-54990?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Microsoft Windows 11 Version 24h2

CVE-2026-54990

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

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Microsoft Windows 11 Version 24h2 — versions 10.0.26100.0
Microsoft Windows 11 Version 25h2 — versions 10.0.26200.0
Microsoft Windows 11 Version 26h1 — versions 10.0.28000.0
Microsoft Windows Server 2025 — versions 10.0.26100.0
Microsoft Windows Server 2025 (Server Core Installation) — versions 10.0.26100.0

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

References

secure@microsoft.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-54990?: CVE-2026-54990 is a critical-severity vulnerability in Microsoft Windows 11 Version 24h2, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-07-14.
How severe is CVE-2026-54990?: Critical severity. CVSS v3 base score is 9.8 out of 10.