# CVE-2026-0390: UEFI Secure Boot Security Feature Bypass Vulnerability

> An authorized local attacker can bypass UEFI Secure Boot protections in the Windows Boot Loader due to reliance on untrusted inputs.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Apr 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-crrm-44jr-89j8

## What is CVE-2026-0390?

CVE-2026-0390 is a medium-severity vulnerability in Microsoft Windows 10 1607, published on 14 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Reliance on untrusted inputs in a security decision in Windows Boot Loader allows an authorized attacker to bypass a security feature locally.

Weakness: CWE-807 (Reliance on Untrusted Inputs in a Security Decision)

## Which versions are affected by CVE-2026-0390?

It affects 7 products.


Products: Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022.

## How do I fix CVE-2026-0390?

No fix has been published for CVE-2026-0390 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-0390 being exploited?

There is no known exploitation of CVE-2026-0390 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Windows 10 1607

- [CVE-2026-33824](https://insights.sbomify.com/CVE-2026-33824/): Microsoft Internet Key Exchange (IKE) Service Extensions Double Free (critical 9.8, exploited in the wild)
- [CVE-2026-21510](https://insights.sbomify.com/CVE-2026-21510/): Microsoft Windows Shell Protection Mechanism Failure (high 8.8, exploited in the wild)
- [CVE-2026-21513](https://insights.sbomify.com/CVE-2026-21513/): Microsoft MSHTML Framework Protection Mechanism Failure (high 8.8, exploited in the wild)
- [CVE-2023-32049](https://insights.sbomify.com/CVE-2023-32049/): Microsoft Windows Defender SmartScreen Security Feature Bypass (high 8.8, exploited in the wild)
- [CVE-2023-29360](https://insights.sbomify.com/CVE-2023-29360/): Microsoft Streaming Service Untrusted Pointer Dereference (high 8.4, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-0390 and fix it if it is affected.

What it is: CVE-2026-0390 is a medium-severity vulnerability in Microsoft Windows 10 1607, published on 14 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-0390 in the wild and no public exploit code.

Affected product: Microsoft Windows 10 1607. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-0390/ (Markdown: https://insights.sbomify.com/CVE-2026-0390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-0390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-0390
- OSV: https://osv.dev/vulnerability/CVE-2026-0390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-0390/
Summaries are generated and may contain mistakes; the official description above is the record.