Vulnerabilities
CVE-2026-83690: Windows Kernel Use‑After‑Free Privilege Escalation
A local use‑after‑free flaw in the Windows kernel allows an attacker with local access to gain SYSTEM privileges. Microsoft has released a patch in the latest cumulative update. Defenders should apply the update immediately and enforce least‑privilege controls.
What happened
An internal use‑after‑free flaw in the Windows kernel was identified. The flaw can be triggered by an attacker with local access to execute code that runs with elevated privileges.
Impact
Any Windows system that has not applied the latest cumulative update is vulnerable. The vulnerability allows a local attacker to gain SYSTEM rights, enabling full control over the affected machine.
Mitigation
- Install the latest security updates from Microsoft (KBxxxx).
- Enable Windows Defender Exploit Guard and the “Kernel Mode Code Signing” policy.
- Apply the principle of least privilege: restrict local admin accounts and enforce MFA for privileged users.
What to do now
Run Windows Update immediately. Verify that the kernel component has been patched. Monitor for suspicious local privilege escalation activity and review audit logs for anomalous SYSTEM‑level processes.
Related vulnerabilities
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A use‑after‑free flaw in Windows Storage allows an authorized local user to elevate privileges. The vulnerability affects Windows 10, 11, Server 2019, and 2022. Defenders should apply the latest cumulative update and enforce least‑privilege policies.
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CVE-2026-70026: Windows Secure Kernel Use‑After‑Free Enables Local Privilege Escalation
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A use‑after‑free flaw in the Windows Win32k kernel subsystem (CVE‑2026‑70076) lets an authorized local attacker gain SYSTEM privileges. The vulnerability is exploitable on all Windows versions that ship the affected Win32k code. Defenders should apply the latest cumulative update and monitor for anomalous privilege escalation.
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