# CVE-2026-45654: Microsoft Windows Secure Boot protection mechanism failure

Source: https://junglewise.ai/threats/cve-2026-45654-microsoft-windows-secure-boot-protection-mechanism-failure  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-45654 · Severity: high · CVSS 7.9 · Published 2026-06-09

A security flaw in Windows Secure Boot could allow an attacker with administrative privileges to bypass critical boot-time protections. Secure Boot is designed to ensure that a computer boots using only software that is trusted by the hardware manufacturer. If exploited, an attacker could potentially undermine the integrity of the operating system and gain persistent control over the device that survives standard security measures.

Technologies: [Microsoft Windows Secure Boot](https://junglewise.ai/threats/technologies/windows-secure-boot). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-45654 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-45654 being exploited in the wild.

**How severe is CVE-2026-45654?** High severity, with a CVSS score of 7.9, published 9 June 2026.

**Which products and versions are affected?** Microsoft Windows Secure Boot.

**Is there a fix for CVE-2026-45654?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-45654 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-45654?** Check whether you run Microsoft Windows Secure Boot. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A protection mechanism failure exists in Windows Secure Boot, classified as improper access control (CWE-284). The vulnerability allows a local attacker with high privileges (Administrator) to bypass Secure Boot integrity checks. By successfully exploiting this flaw, an attacker can load unauthorized software during the boot process, potentially leading to the installation of bootkits or other persistent malware that operates outside the visibility of the operating system. The attack requires local access and high-level permissions but results in a scope change (S:C), impacting the underlying hardware/firmware trust boundary. Microsoft has released information regarding this vulnerability via their Security Update Guide.

## Affected products

- Microsoft Windows Secure Boot

## Timeline

- 2026-06-09: disclosed
- 2026-06-09: advisory

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45654](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45654)

## Related threats

- [Microsoft Windows Secure Boot protection mechanism failure](https://junglewise.ai/threats/cve-2026-48578-microsoft-windows-secure-boot-protection-mechanism-failure)
- [Microsoft Windows Secure Boot protection mechanism failure](https://junglewise.ai/threats/cve-2026-48575-microsoft-windows-secure-boot-protection-mechanism-failure)
- [Microsoft Windows Secure Boot protection mechanism failure](https://junglewise.ai/threats/cve-2026-45588-microsoft-windows-secure-boot-protection-mechanism-failure)
- [Microsoft Windows Secure Boot security feature bypass](https://junglewise.ai/threats/cve-2026-41097-microsoft-windows-secure-boot-security-feature-bypass)