# CVE-2026-45498: Microsoft Defender Denial of Service

> Attackers can cause a denial of service in Microsoft Defender Antimalware Platform, requiring users to apply vendor patches.

- **Severity:** Medium 4.0 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Yes, since 20 May 2026 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 May 2026
- **Updated:** 10 Aug 2026
- **Also known as:** GHSA-8gp3-pghr-6wxp

## What is CVE-2026-45498?

CVE-2026-45498 is a medium-severity denial of service vulnerability in Microsoft Defender Antimalware Platform, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Microsoft Defender Denial of Service Vulnerability

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-45498?

It affects 1 product.


Products: Microsoft Defender Antimalware Platform.

## How do I fix CVE-2026-45498?

No fix has been published for CVE-2026-45498 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 3 Jun 2026.

## Is CVE-2026-45498 being exploited?

Yes. Attackers have exploited CVE-2026-45498 in the wild since at least 20 May 2026.

Public exploit code:

- DESIGN AND IMPLEMENTATION OF A VULNERABILITY SCANNER FOR CVE-2026-45498 IN MICROSOFT DEFENDER (github_poc): https://github.com/salihuahmad105-creator/Vulnerability-scanner

## Other vulnerabilities in Microsoft Defender Antimalware Platform

- [CVE-2026-33825](https://insights.sbomify.com/CVE-2026-33825/): Microsoft Defender Insufficient Granularity of Access Control (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45498 and fix it if it is affected.

What it is: CVE-2026-45498 is a medium-severity denial of service vulnerability in Microsoft Defender Antimalware Platform, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2026-45498 in the wild since at least 20 May 2026.

Affected product: Microsoft Defender Antimalware Platform. 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-2026-45498/ (Markdown: https://insights.sbomify.com/CVE-2026-45498/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45498
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45498
- OSV: https://osv.dev/vulnerability/CVE-2026-45498

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45498/
Summaries are generated and may contain mistakes; the official description above is the record.