Secure Boot Bypass Vulnerability in Microsoft UEFI SHIM Bootloaders
CVE-2026-8863

7.8HIGH

Key Information:

Vendor

Oracle
Status
Oraclelinux(7.2) Shim
Service Center Enterprise
Service Center Drive Erase
Service Center Japan
Vendor
CVE Published:
9 June 2026

What is CVE-2026-8863?

Multiple UEFI SHIM bootloaders from Microsoft are susceptible to a Secure Boot bypass issue. If an attacker possesses administrative rights or can manipulate the boot sequence, they may exploit these vulnerable bootloaders to circumvent Secure Boot protections. This exploit allows the execution of arbitrary code prior to the loading of the operating system, creating significant security risks. It is crucial to implement the specified UEFI DBX update to mitigate this vulnerability effectively.

Affected Version(s)

Abitti 1 1.0.0

baramundi Management Suite * <= 2024R1

Factory for Linux (Bootable Diagnostics) 6.9 <= 6.20.7710.267

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisory
https://kb.cert.org/vuls/id/616257
third-party-advisory

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Thanks to Martin Smolar of ESET for discovering and reporting this vulnerability
.