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CVE-2026-10797 is a legacy flaw in the Linux shim UEFI bootloader, affecting old Microsoft-signed shim builds primarily based on version 0.9 and earlier. The vulnerability lies in shim's certificate-based revocation logic for second-stage PE bootloaders: an Authenticode-signed PE binary stores signature length information in two separate structures, and vulnerable shim code reads the signature size from the wrong PE structure during revocation checking while using different data during signature verification. By tampering with the second-stage bootloader's WIN_CERTIFICATE header, an attacker can cause shim to compare dbx or MokListX revocation entries against bogus certificate data instead of the bootloader's actual signature. This allows a revoked or otherwise blocked second-stage boot component to pass the revocation check while still being accepted as signed. In practice, the flaw undermines UEFI Secure Boot trust decisions in environments that continue to trust old Microsoft-signed shim binaries.
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A Secure Boot bypass vulnerability affecting old Microsoft-signed UEFI shim bootloaders, allowing execution of untrusted code during boot on systems that trust the Microsoft third-party UEFI certificate.
A vulnerability designation associated with old and forgotten Linux UEFI shim bootloaders (versions 0.9 and below) that can be abused to bypass UEFI Secure Boot on systems trusting Microsoft's third-party UEFI CA, enabling execution of untrusted code during boot and deployment of malicious UEFI bootkits.
A vulnerability designation covering Microsoft-signed vulnerable UEFI shim bootloaders that can be abused to bypass UEFI Secure Boot and load untrusted code during boot.
A revocation-check flaw in old UEFI shim bootloaders where the shim reads signature size from the wrong PE structure, allowing attackers to bypass dbx/MokListX revocation checks.
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Every observed campaign linking this CVE to a named adversary.
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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.