UEFI Secure Boot Security Feature Bypass in Windows Boot Loader
CVE-2026-0390 is an Important security feature bypass vulnerability in the Windows Boot Loader, described by Microsoft as caused by reliance on untrusted inputs in a security decision. The issue affects the UEFI Secure Boot trust path in Windows Boot Loader and allows a locally authorized attacker to bypass a security mechanism. Available advisory context indicates the flaw is tied to an authentication-related feature in the boot process and can enable impersonation. No specific vulnerable function or code path was provided in the supplied content.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Windows Boot Loader security feature bypass vulnerability affecting the Secure Boot chain of trust.
A UEFI Secure Boot security feature bypass vulnerability.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.