CVE-2026-8863

7.8 HIGH

Multiple Microsoft-sigend UEFI SHIM bootloaders are vulnerable to SecureBoot bypass

Published: 2026-06-09 · Last updated: 2026-06-09

Severity and scoring

CVSS: 7.8 HIGH
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Description

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.

Source: NVD

References

[NVD]https://nvd.nist.gov/vuln/detail/CVE-2026-8863
[Other]https://kb.cert.org/vuls/id/616257
[Other]https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-8863
[Other]https://www.kb.cert.org/vuls/id/616257