---
id: CVE-2026-45584
title: >-
  Heap-based buffer overflow in Microsoft Defender allows an unauthorized
  attacker to execute code over a network.
summary: >-
  Heap-based buffer overflow in Microsoft Defender allows an unauthorized
  attacker to execute code over a network.
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-122
vendor: microsoft
product: malware_protection_engine
affected:
  - 'malware_protection_engine >= 1.1.26030.3008, < 1.1.26040.8'
patched:
  - malware_protection_engine 1.1.26040.8
published: '2026-05-20'
updated: '2026-07-23'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-45584'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45584'
    label: secure@microsoft.com
tags:
  - nvd
  - exploit-available
epss: 0.00707
epssPercentile: 0.51364
ingestedAt: '2026-07-23T12:17:54.861Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/96613686/CVE-2026-45584'
  checkedAt: '2026-09-25T08:20:58.190Z'
exploitAvailable: true
---

## Overview

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

## Affected

- `malware_protection_engine >= 1.1.26030.3008, < 1.1.26040.8`

## Remediation

Upgrade past the affected range:

- `malware_protection_engine 1.1.26040.8`