Out-of-bounds read in Windows and Windows Server - CVE-2026-45607

Vulnerability identifier: #VU134021

CSH Severity: High

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-45607

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in Windows Hyper-V. A remote attacker can trigger an out-of-bounds read error and read contents of memory on the system, leading to arbitrary code execution.

Windows
Windows Server

Install updates from vendor's website.

Windows - addressed in versions 10 21H2 10.0.19044.7417, 10 22H2 10.0.19045.7417, 10 1607 10.0.14393.9234, 10 1809 10.0.17763.8880, 11 23H2 10.0.22631.7219, 11 24H2 10.0.26100.8655, 11 25H2 10.0.26200.8655, 11 26H1 10.0.28000.2269
Windows Server - addressed in versions 2012 R2 6.3.9600.23228, 2016 10.0.14393.9234, 2019 10.0.17763.8880, 2022 10.0.20348.5256, 2025 10.0.26100.32995

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45607