CVE-2026-40402
CriticalWhat is CVE-2026-40402?
Use after free in Windows Hyper-V allows an unauthorized attacker to elevate privileges locally.
CVSS Vector Breakdown
CVSS 3.1Requires local access — attacker must be logged in or have physical access to the device.
No special conditions required. Exploit can be performed reliably and repeatedly.
No authentication required. Any anonymous user can exploit this vulnerability.
No user interaction required. Exploit runs without any victim action.
Exploiting the vulnerability can affect other components beyond the vulnerable one.
Complete loss of confidentiality. All data on the component may be exposed.
Complete loss of integrity. Attacker can modify any file or data on the component.
Complete denial of service. The component becomes fully unavailable.
FAQ
CVE-2026-40402 has a CVSS score of 9.3/10, rated as Critical. This is the highest severity level - immediate patching is strongly recommended.
CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2026-40402 scores 9.3/10 (Critical). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.
The list of devices confirmed to be affected by CVE-2026-40402 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.
Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.