# CVE-2019-1019: Microsoft Windows Security Feature Bypass Vulnerability

> An attacker can bypass NTLM security features to access another machine with original user privileges via a crafted NETLOGON message.

- **Severity:** High 8.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jun 2019
- **Updated:** 20 May 2025
- **Also known as:** GHSA-5fqm-f4f4-5vpq

## What is CVE-2019-1019?

CVE-2019-1019 is a high-severity vulnerability in Microsoft Windows 10, published on 12 Jun 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security feature bypass vulnerability exists where a NETLOGON message is able to obtain the session key and sign messages.
To exploit this vulnerability, an attacker could send a specially crafted authentication request. An attacker who successfully exploited this vulnerability could access another machine using the original user privileges.
The issue has been addressed by changing how NTLM validates network authentication messages.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2019-1019?

It affects 8 products.


Products: Microsoft Windows 10, Microsoft Windows 7, Microsoft Windows 8.1, Microsoft Windows Rt 8.1, Microsoft Windows Server 2008, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019.

## How do I fix CVE-2019-1019?

No fix has been published for CVE-2019-1019 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1019 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-1019 exists.

Public exploit code:

- Microsoft Windows 10.0.17134.648 - HTTP -> SMB NTLM Reflection Leads to Privilege Elevation (exploitdb)

## Other vulnerabilities in Microsoft Windows 10

- [CVE-2015-2426](https://insights.sbomify.com/CVE-2015-2426/): Microsoft Windows Adobe Type Manager Library Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2015-1769](https://insights.sbomify.com/CVE-2015-1769/): Microsoft Windows Mount Manager Privilege Escalation (medium 6.6, exploited in the wild)
- [CVE-2020-1467](https://insights.sbomify.com/CVE-2020-1467/): Windows Hard Link Elevation of Privilege Vulnerability (critical 10.0)
- [CVE-2021-26424](https://insights.sbomify.com/CVE-2021-26424/): Windows TCP/IP Remote Code Execution Vulnerability (critical 9.9)
- [CVE-2021-28476](https://insights.sbomify.com/CVE-2021-28476/): Windows Hyper-V Remote Code Execution Vulnerability (critical 9.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1019 and fix it if it is affected.

What it is: CVE-2019-1019 is a high-severity vulnerability in Microsoft Windows 10, published on 12 Jun 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-1019 exists.

Affected product: Microsoft Windows 10. 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-2019-1019/ (Markdown: https://insights.sbomify.com/CVE-2019-1019/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1019
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1019
- OSV: https://osv.dev/vulnerability/CVE-2019-1019

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-1019/
Summaries are generated and may contain mistakes; the official description above is the record.