Vulnerability Report

CVE-2026-8863

RCE

Title: Microsoft-signed UEFI SHIM SecureBoot Bypass

RCE

Proof Of Concept

PoC Available for CVE-2026-8863

CWE Category NVD-CWE-noinfo

Published Date Jun 09, 2026

Modified Date Jul 23, 2026

Exploit Status Available

Score 7.8 CVSS v

Exploit Probability (EPSS)

0.11%

Vulnerability Summary

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.

Impacted Vendors

Analysis in Progress...

Reference Links

https://kb.cert.org/vuls/id/616257 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-8863

CVSS v3.1

Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0

Severity HIGH

7.8

Attack Vector

LOCAL

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-8863 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/0xbekoo/CVE-2026-8863

View Code

July 23, 2026 MODIFIED

Vulnerability data updated via NVD.

June 09, 2026 MODIFIED

Vulnerability data updated via NVD.

June 09, 2026 MODIFIED

Vulnerability data updated via NVD.

June 09, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector LOCAL

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


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

Affected Stack

No specific products linked.