GHSA-7fcj-pq9j-wh2r is a high-severity (CVSS 7) CWE-250 vulnerability in pyinstaller. O3 Security confirms whether GHSA-7fcj-pq9j-wh2r is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Local Privilege Escalation in PyInstaller
Real-World Exposure
pyinstallerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Local Privilege Escalation in all Windows software frozen by PyInstaller in "onefile" mode.
The vulnerability is present only on Windows and in this particular case: If a software frozen by PyInstaller in "onefile" mode is launched by a (privileged) user who has his/her "TempPath" resolving to a world writable directory. This is the case e.g. if the software is launched as a service or as a scheduled task using a system account (in which case TempPath will default to C:\Windows\Temp).
In order to be exploitable the software has to be (re)started after the attacker has launched the exploit program. So for a service launched at startup, a service restart is needed (e.g. after a crash or an upgrade).
While PyInstaller itself was not vulnerable, all Windows software frozen by PyInstaller in "onefile" mode is vulnerable.
CVSSv3 score 7.0 (High) CVSSv3 vector CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected
- all Windows software frozen by PyInstaller in "onefile" mode
No affected
- PyInstaller itself (except if frozen by PyInstaller in "onefile" mode on Windows)
- software frozen in "onedir" mode
- other platforms (GNU/Linux, OS X, BSD, etc.)
Patches
The problem is patched in commits 42a67148b3bdf9211fda8499fdc5b63acdd7e6cc (fixed code) and be948cf0954707671aa499da17b10c86b6fa5e5c (recompiled bootloaders). Users should upgrade to PyInstaller version 3.6 and rebuild their software.
Workarounds
There is no known workaround. Users using PyInstaller to freeze their Windows software using "onefile" mode should upgrade PyInstaller and rebuild their software.
Credits
This vulnerability was discovered and reported by Farid AYOUJIL (@faridtsl), David HA, Florent LE NIGER and Yann GASCUEL (@lnv42) from Alter Solutions (@AlterSolutions) and fixed in collaboration with Hartmut Goebel (@htgoebel, maintainer of PyInstaller).
Funding Development
PyInstaller is in urgent need of funding to make future security fixes happen, see https://github.com/pyinstaller/pyinstaller/issues/4404 for details.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyinstaller | all versions | 3.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyinstaller. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pyinstaller to 3.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7fcj-pq9j-wh2r 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 pinpoints whether GHSA-7fcj-pq9j-wh2r is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-7fcj-pq9j-wh2r. 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-7fcj-pq9j-wh2r in your dependencies?
O3 detects GHSA-7fcj-pq9j-wh2r across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.