CVE-2026-6485Public exploit

Secure Boot bypass via embedded UEFI Shell

Published Sep 9, 2026 · Updated Sep 10, 2026

Secure Boot bypass in Insyde Software InsydeH2O allows local users with administrator access to execute unsigned pre-OS code. Firmware builds that embed the UEFI Shell in Secure Boot-approved SPI-flash regions expose shell commands and startup scripts that can overwrite Secure Boot-related memory values. Exploitation requires control of UEFI boot entries and an affected customer build containing the trusted shell; successful use permits unauthorized code execution before the operating system loads.

CVSS severity8.2
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Secure Boot bypass in Insyde Software InsydeH2O allows local users with administrator access to execute unsigned pre-OS code. Firmware builds that embed the UEFI Shell in Secure Boot-approved SPI-flash regions expose shell commands and startup scripts that can overwrite Secure Boot-related memory values. Exploitation requires control of UEFI boot entries and an affected customer build containing the trusted shell; successful use permits unauthorized code execution before the operating system loads.

The record

CVE
CVE-2026-6485
Published
Sep 9, 2026
Updated
Sep 10, 2026
Vendor
Insyde Software
Product
InsydeH2O UEFI BIOS
Classifications
CWE-489, T1542.001
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=See in the Solution

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Insyde Software · InsydeH2O UEFI BIOSversion=See in the Solution

Published CVSS scores

8.2Insyde SoftwareCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-489Active Debug Code
T1542.001Pre-OS Boot: System Firmware

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo