CVE-2026-42171
NSIS (Nullsoft Scriptable Install System) 3.06.1 before 3.12 sometimes uses the Low IL temp...
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).
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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).
- Record
CVE-2026-42171- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-427
- Updated
- 2026-11-02
EUVDEUVD-2026-25637
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).
- Record
EUVD-2026-25637- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-594m-24qw-wfmp
NSIS (Nullsoft Scriptable Install System) 3.06.1 before 3.12 sometimes uses the Low IL temp...
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).
- Record
GHSA-594m-24qw-wfmp- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-427
- Updated
- 2026-11-02
NVD
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).
- Record
CVE-2026-42171- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-427
- Updated
- 2026-11-02
OSV
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).
- Record
CVE-2026-42171- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-427
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-42171
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).
- Record
DEBIAN-CVE-2026-42171- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-42171
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).
- Record
UBUNTU-CVE-2026-42171- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
nsisDebian:12 |
All versions, plus listed versions 3.08-33.08-3+deb12u13.09-13.09-23.09-3 Show 5 moreShow less3.09-43.10-13.10-23.11-13.12-1 |
None known |
nsisDebian:13 |
All versions, plus listed versions 3.11-13.12-1 |
None known |
nsisDebian:14 |
before 3.12-1, plus listed versions 3.11-1 |
3.12-1 |
nsisUbuntu:Pro:14.04:LTS |
All versions, plus listed versions 2.46-72.46-7ubuntu0.1~esm1 |
None known |
nsisUbuntu:16.04:LTS |
All versions, plus listed versions 2.46-10.12.48-22.50-1 |
None known |
nsisUbuntu:18.04:LTS |
All versions, plus listed versions 2.51-1 |
None known |
nsisUbuntu:20.04:LTS |
All versions, plus listed versions 3.04-13.04-23.05-13.05-2 |
None known |
nsisUbuntu:22.04:LTS |
All versions, plus listed versions 3.06.1-13.08-13.08-2 |
None known |
nsisUbuntu:24.04:LTS |
All versions, plus listed versions 3.09-13.09-23.09-33.09-43.09-4ubuntu1 |
None known |
nsisUbuntu:25.10 |
All versions, plus listed versions 3.10-2ubuntu1 |
None known |
nsisUbuntu:26.10 |
All versions, plus listed versions 3.10-2ubuntu2 |
None known |
nsisUbuntu:26.04:LTS |
All versions, plus listed versions 3.10-2ubuntu13.10-2ubuntu2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-42171 is a high vulnerability (CVSS 7.8) in Nullsoft Scriptable Install System, published April 24, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 11th percentile. Fixed in nsis 3.12-1.
References
nsis.sourceforge.io/Docs/AppendixF.html
github.com/NSIS-Dev/nsis/commit/8e6f02205d5f22da6c7855dbfe59b2af667330ca
learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-gettempfilename
nvd.nist.gov/vuln/detail/CVE-2026-42171