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CVE-2026-48575 is a vulnerability in Microsoft Windows Secure Boot that allows an authorized attacker to bypass the platform’s core security feature. Secure Boot is a UEFI firmware mechanism that ensures only trusted, digitally signed bootloaders, drivers, and OS kernels are loaded during system startup. The flaw stems from a protection mechanism failure, meaning that the UEFI firmware does not properly enforce the signature verification process under certain conditions.
An attacker requires local access and high privileges—such as administrative or SYSTEM rights—to exploit this vulnerability. Once those are obtained, the attacker can manipulate the Secure Boot policy or its authenticated variables. For example, the attacker could enroll a rogue signing certificate into the Secure Boot database (db), effectively tricking the system into trusting malicious boot components as if they were legitimately signed by Microsoft. Alternatively, the attacker might exploit a race condition or a logic error in the boot manager to bypass signature checks entirely.
The impact is severe: the attacker can load unsigned or tampered boot components, including custom bootkits, that reside below the operating system. Such malware persists across OS reinstalls and remains invisible to traditional security tools. The vulnerability affects a wide range of Windows versions, including Windows 10, Windows 11, and Windows Server 2012 through 2025, across x86, x64, and arm64 architectures where Secure Boot is enabled.
The CVSS 3.x vector is AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N, resulting in a base score of 7.9 (High). This reflects low attack complexity, high privilege requirement, no user interaction, a changed scope, and high impacts on confidentiality and integrity but no impact on availability.
DailyCVE Form:
Platform: Microsoft Windows
Version: 10,11,Server 2025
Vulnerability: Secure Boot bypass
Severity: High (CVSS 7.9)
date: June 9, 2026
Prediction: June 2026 Patch Tuesday
What Undercode Say:
Check Secure Boot status
Confirm-SecureBootUEFI
List UEFI Secure Boot variables
Get-SecureBootUEFI -Name db
Enumerate boot components for analysis
Get-WindowsDriver -Online | Where-Object { $_.BootCritical -eq $true }
Simulate policy manipulation (requires admin)
Set-SecureBootUEFI -Name PK -Content ([System.Text.Encoding]::ASCII.GetBytes("malicious"))
CVE-2026-48575 verification snippet
$sbStatus = Confirm-SecureBootUEFI
if ($sbStatus -eq $true) {
Write-Host "Secure Boot enabled – but CVE-2026-48575 may still allow bypass."
} else {
Write-Host "Secure Boot disabled – no CVE-2026-48575 protection."
}
Exploit:
An attacker with local administrative privileges can exploit CVE-2026-48575 by modifying the Secure Boot authenticated variables (e.g., the `db` variable) to add a self-signed certificate. Then, the attacker replaces the legitimate bootloader with an unsigned malicious payload, which the compromised Secure Boot process loads without error. This results in a persistent bootkit that executes before the OS kernel.
Protection:
Apply the June 2026 Windows security update from Microsoft immediately. Ensure UEFI firmware is updated to the latest vendor release. Enable Secure Boot and restrict physical access to the system. Monitor Event ID 1 (Secure Boot variable changes) and Event ID 1035 (boot policy violations) using Windows Event Viewer.
Impact:
Successful exploitation allows loading unsigned boot components, enabling persistent bootkits that survive OS reinstallation, evade antivirus and EDR, and provide low-level system control. This undermines all higher-layer security mechanisms, including BitLocker, Hypervisor-Protected Code Integrity (HVCI), and Kernel Patch Protection (PatchGuard).
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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