CVE-2026-42171
Severity CVSS v4.0:
Pending analysis
Type:
CWE-427
Uncontrolled Search Path Element
Publication date:
24/04/2026
Last modified:
24/04/2026
Description
NSIS (Nullsoft Scriptable Install System) 3.06.1 before 3.12 sometimes uses the Low IL temp directory when executing as SYSTEM, allowing local attackers to gain privileges (if they can cause my_GetTempFileName to return 0, as shown in the references).
Impact
Base Score 3.x
7.80
Severity 3.x
HIGH
References to Advisories, Solutions, and Tools
- https://github.com/NSIS-Dev/nsis/blob/7359413009afd4f0fff472d841fc2f2cc0e0a5f8/Source/exehead/util.c#L475-L484
- https://github.com/NSIS-Dev/nsis/commit/8e6f02205d5f22da6c7855dbfe59b2af667330ca
- https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-gettempfilename
- https://nsis.sourceforge.io/Docs/AppendixF.html#v3.12-cl



