Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-113856
Published: November 11, 2026
Vulnerability identifier: #VU164956
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-113856
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges from a guest virtual machine to the host.
The vulnerability exists due to a heap-based buffer overflow in Windows Hyper-V when processing operations initiated inside a guest virtual machine. A local user can trigger the overflow from within the guest to execute code on the host in the security context of the virtual machine worker process.
Successful exploitation requires winning a race condition.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-113856
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7846, 10 22H2 10.0.19045.7846, 11 23H2 10.0.22631.7711, 11 24H2 10.0.26100.9911, 11 24H2 10.0.26100.9974, 11 25H2 10.0.26200.9911, 11 25H2 10.0.26200.9974, 11 26H1 10.0.28000.3501
Windows Server - addressed in versions 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822
Windows Server - addressed in versions 2022 10.0.20348.5870, 2025 10.0.26100.33730, 2025 10.0.26100.33822