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CVE-2026-42171

Published: Apr 24, 2026Updated: May 18, 2026 Sources: CVE List NVDCWE-427
NVD MITRE
7.8CVSSHIGH
EPSS Score
0.2%
Top 89.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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).

CVSS Vector Breakdown

AV:LAC:LPR:NUI:RS:UC:HI:HA:H
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-427

Affected Products

nullsoft scriptable install systemnullsoft
Mixed
Consumer Software / media-player
Nullsoft Scriptable Install SystemNullsoft
Mixed
Consumer Software / media-player
nullsoftcommercialConsumer Softwareaka winamp, shoutcast server

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Persistence
View detailed technique mapping

References

https://github.com/NSIS-Dev/nsis/blob/7359413009afd4f0fff472d841fc2f2cc0e0a5f8/Source/exehead/util.c#L475-L484
github.com
https://github.com/NSIS-Dev/nsis/commit/8e6f02205d5f22da6c7855dbfe59b2af667330ca
github.com
https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-gettempfilename
learn.microsoft.com
and 1 more references View all →

Timeline

Published
Apr 24, 2026
Last Updated
May 18, 2026

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