VU#687587: AOMEI Backupper amwrtdrv.sys local privilege escalation vulnerability allows arbitrary writes to physical disks
AOMEI Backupper 8.4.0 driver flaw CVE-2026-12780 lets unprivileged users write physical disks and execute UEFI code, bypassing HVCI and EDR.
CERT/CC issued VU#687587 for CVE-2026-12780, an incorrect permission assignment (CWE-732) in the amwrtdrv.sys kernel driver shipped with AOMEI Backupper 8.4.0. The driver exposes a world-accessible device object without a security descriptor, allowing any unprivileged user to write arbitrary physical disk sectors; with Secure Boot disabled, an attacker can modify the GPT and inject a UEFI payload that executes before the OS loads, bypassing HVCI, EDR, Windows Defender and Hyper-V isolation. On TPM-only BitLocker configurations the attack can capture Volume Master Key material during pre-boot. AOMEI has shipped patches; users who cannot update should uninstall the software or disable the amwrtdrv.sys service, and enabling Secure Boot adds defense in depth.
Microsoft releases Windows 10 KB5122878 extended security update
Microsoft shipped Windows 10 ESU update KB5122878, delivering the record September 2026 Patch Tuesday fixes, including patches for two actively exploited zero-days.
Microsoft released KB5122878 for Windows 10 Enterprise LTSC and ESU customers, moving builds 19045/19044 to .7725 with security and bug fixes. The update carries this month's record September 2026 Patch Tuesday set, which fixed 966 Microsoft vulnerabilities including two actively exploited zero-day flaws. It also fixes BitLocker recovery-key prompts and Remote Desktop audio redirection, and updates Secure Boot certificate rollout and Morocco time zone data. Microsoft reports no known issues with the update.
ShieldBreak: New Windows Zero-Day Bypasses Microsoft’s RoguePlanet Patch
Researcher Chaotic Eclipse published a PoC bypassing Microsoft's CVE-2026-50656 Defender patch, enabling SYSTEM-level code execution on fully patched Windows systems.
Security researcher Chaotic Eclipse released a proof-of-concept for ShieldBreak, a Microsoft Defender zero-day that fully bypasses the patch for CVE-2026-50656 (RoguePlanet), a race condition in the Malware Protection Engine (mpengine.dll) allowing SYSTEM-level code execution. The PoC was tested on Windows 11 25H2 and Windows Server 2025 with a 100% success rate, and Windows 10 is also vulnerable though not supported by the PoC; the flaw may also leak 8 bytes of memory. Microsoft's MSRC had criticized the researcher's repeated uncoordinated disclosures, including YellowKey (BitLocker bypass), GreenPlasma, and LegacyHive (User Profile Service LPE).