CVE-2026-8863

Multiple Microsoft-sigend UEFI SHIM bootloaders are vulnerable to SecureBoot bypass. An attacker with administrative privileges or the ability to modify the boot process could use one of the vulnerable shim bootloaders to bypass Secure Boot protections and execute arbitrary code before the operating system loads. Specific UEFI DBX update is required to block these vulnerable boot loaders.

• Published Jun 9, 2026
• CVSS 7.8 high
• 0.1% chance of exploitation in the next 30 days (EPSS)

CVE-2026-8863 at the National Vulnerability Database