# CVE-2026-58638: Microsoft Windows Boot Loader security feature bypass

Source: https://junglewise.ai/threats/cve-2026-58638-microsoft-windows-boot-loader-security-feature-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-14. Updated: 2026-07-14  
License: CC BY 4.0 with a link back

CVE-2026-58638 · Severity: medium · CVSS 6 · Published 2026-07-14

A security bypass vulnerability exists in the Windows Boot Loader, the component responsible for starting the operating system securely. An attacker who already has high-level administrative access to a computer could exploit this to bypass built-in security protections. This could allow them to gain deeper control over the system or access sensitive information that is normally protected during the startup process.

Technologies: [Microsoft Windows 11](https://junglewise.ai/threats/technologies/windows-11), [Microsoft Windows 10](https://junglewise.ai/threats/technologies/windows-10), [Microsoft Windows Server 2012](https://junglewise.ai/threats/technologies/windows-server-2012). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-58638 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-58638 being exploited in the wild.

**How severe is CVE-2026-58638?** Medium severity, with a CVSS score of 6, published 14 July 2026.

**Which products and versions are affected?** Microsoft Windows 11 24H2, 25H2, 26H1; Microsoft Windows 10 1809, 21H2, 22H2; Microsoft Windows Server 2012 Standard, R2, Server Core.

**Is there a fix for CVE-2026-58638?** A patch was published on 2026-07-14: Security updates released by Microsoft Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-58638 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-58638?** Check whether you run Microsoft Windows 11, Microsoft Windows 10 or Microsoft Windows Server 2012 at an affected version. 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

This vulnerability is classified as a missing cryptographic step (CWE-325) within the Windows Boot Loader. An attacker with high privileges (PR:H) can exploit this flaw locally to bypass security features, potentially compromising the integrity of the boot process. The vulnerability affects multiple versions of Windows 10, Windows 11, and Windows Server 2012. Exploitation requires local access but no user interaction. Microsoft has released security updates to address this issue by ensuring the necessary cryptographic steps are performed during boot.

## Affected products

- Microsoft Windows 10 1809, 21H2, 22H2
- Microsoft Windows 11 24H2, 25H2, 26H1
- Microsoft Windows Server 2012 Standard, R2, Server Core

## Timeline

- 2026-07-14: advisory: Initial disclosure by Microsoft and NVD
- 2026-07-14: patched: Security updates released by Microsoft

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58638](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58638)

## Related threats

- [Microsoft Windows Recovery Environment UEFI/BIOS password bypass](https://junglewise.ai/threats/cve-2026-116638-the-windows-recovery-environment-winre-in-windows-10-and-11-may)
- [Windows DNS Server out-of-bounds read](https://junglewise.ai/threats/cve-2026-97844-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-97843-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-97842-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read](https://junglewise.ai/threats/cve-2026-97841-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)