# CVE-2026-45584: Microsoft Defender Remote Code Execution Vulnerability

> An unauthorized attacker can execute arbitrary code remotely via a heap-based buffer overflow in the Microsoft Malware Protection Engine.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 May 2026
- **Updated:** 10 Aug 2026
- **Also known as:** GHSA-f7rp-9ghh-f4gm

## What is CVE-2026-45584?

CVE-2026-45584 is a high-severity memory corruption vulnerability in Microsoft Malware Protection Engine, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Heap-based buffer overflow in Microsoft Defender allows an unauthorized attacker to execute code over a network.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-45584?

It affects 1 product.


Products: Microsoft Malware Protection Engine.

## How do I fix CVE-2026-45584?

No fix has been published for CVE-2026-45584 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-45584 being exploited?

There is no known exploitation of CVE-2026-45584 in the wild and no public exploit code.

Public exploit code:

- https://github.com/96613686/CVE-2026-45584 (github_poc): https://github.com/96613686/CVE-2026-45584

## Other vulnerabilities in Microsoft Malware Protection Engine

- [CVE-2026-41091](https://insights.sbomify.com/CVE-2026-41091/): Microsoft Defender Link Following (high 7.8, exploited in the wild)
- [CVE-2013-1346](https://insights.sbomify.com/CVE-2013-1346/): Memory corruption in n/a (critical 9.3)
- [CVE-2026-69414](https://insights.sbomify.com/CVE-2026-69414/): Microsoft Defender Elevation of Privilege Vulnerability (high 7.8)
- [CVE-2026-55011](https://insights.sbomify.com/CVE-2026-55011/): Microsoft Defender Remote Code Execution Vulnerability (high 7.8)
- [CVE-2026-55012](https://insights.sbomify.com/CVE-2026-55012/): Microsoft Defender Remote Code Execution Vulnerability (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45584 and fix it if it is affected.

What it is: CVE-2026-45584 is a high-severity memory corruption vulnerability in Microsoft Malware Protection Engine, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-45584 in the wild and no public exploit code.

Affected product: Microsoft Malware Protection Engine. 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-2026-45584/ (Markdown: https://insights.sbomify.com/CVE-2026-45584/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45584
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45584
- OSV: https://osv.dev/vulnerability/CVE-2026-45584

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45584/
Summaries are generated and may contain mistakes; the official description above is the record.