May 28, 2026 · Information Security

12‑Byte Syscall in Browser Sandbox Grants SYSTEM on Windows (CVE‑2026‑40369 PoC)

The article details CVE‑2026‑40369, a Windows kernel flaw in ExpGetProcessInformation where a zero‑length buffer bypasses ProbeForWrite, allowing a browser sandbox process to write arbitrary kernel memory with a 12‑byte syscall, leading to a deterministic, fully‑reliable privilege‑escalation chain that grants SYSTEM without race conditions, and discusses detection and mitigation.

CVE-2026-40369NtQuerySystemInformationWindows kernel

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12‑Byte Syscall in Browser Sandbox Grants SYSTEM on Windows (CVE‑2026‑40369 PoC)

Black & White Path

May 18, 2026 · Information Security

Windows Kernel LPE (CVE‑2026‑40369) PoC: Privilege Escalation from Chrome Sandbox

CVE‑2026‑40369 is an arbitrary kernel‑address write bug in ntoskrnl.exe that lets a low‑privilege attacker invoke NtQuerySystemInformation from the Chrome sandbox to gain SYSTEM rights on vulnerable Windows 11 and Server 2025 builds, with a fully functional PoC released on GitHub.

CVE-2026-40369Chrome sandboxLocal Privilege Escalation

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Windows Kernel LPE (CVE‑2026‑40369) PoC: Privilege Escalation from Chrome Sandbox