GHSA-rf39-3f98-xr7r is a high-severity (CVSS 7.3) CWE-732 vulnerability in wix. A fix is available for wix — see the affected versions and patch details below.
WiX based installers are vulnerable to binary hijack when run as SYSTEM
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-rf39-3f98-xr7r.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-rf39-3f98-xr7r plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
wix.NETwix.NETWixToolset.SdkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Burn uses an unprotected C:\Windows\Temp directory to copy binaries and run them from there. This directory is not entirely protected against low privilege users.
Details
When a bundle runs as SYSTEM user, Burn uses GetTempPathW which points to an insecure directory C:\Windows\Temp to drop and load multiple binaries. Standard users can hijack the binary before it's loaded in the application resulting in elevation of privileges.
icacls c:\windows\temp
BUILTIN\Users:(CI)(S,WD,AD,X) BUILTIN\Administrators:(F) BUILTIN\Administrators:(OI)(CI)(IO)(F) NT AUTHORITY\SYSTEM:(F) NT AUTHORITY\SYSTEM:(OI)(CI)(IO)(F) CREATOR OWNER:(OI)(CI)(IO)(F)
Built in users(non-administrators) have special permissions to this folder and can create files and write to this directory. While they do not have explicit read permissions, there is a way they can monitor the changes to this directory using ReadDirectoryChangesW API and thus figure out randomized folder names created inside this directory as wel
PoC
PoC works against the against visual studio enterprise with update 3 installer
Reproduction steps
As a standard user, run the poc. Mount the iso and run visual studio installer as local system account. The PoC should hijack the the binaries dropped by vs installer and a child process "notepad.exe" will be running.
Impact
This is an Elevation of Privilege Vulnerability where a low privileged user can hijack binaries in an unprotected path C:\Windows\Temp to elevate to the SYSTEM user privileges.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | wix | all versions | 3.14.1dotnet add package wix --version 3.14.1 |
| .NETNuGet | wix | ≥ 4.0.0&&< 4.0.5 | 4.0.5dotnet add package wix --version 4.0.5 |
| .NETNuGet | WixToolset.Sdk | all versions | 4.0.5dotnet add package WixToolset.Sdk --version 4.0.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wix, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update wix to 3.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rf39-3f98-xr7r is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-rf39-3f98-xr7r can be triaged on real exposure rather than presence alone.
Tailored to GHSA-rf39-3f98-xr7r. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-rf39-3f98-xr7r in your dependencies?
O3 Security finds GHSA-rf39-3f98-xr7r across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.