CVE-2019-16784

HIGH

PyInstaller <3.6 - Privilege Escalation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2019-16784. PoCs published by AlterSolutions, Ckrielle.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2019-16784, a PyInstaller privilege escalation vulnerability. The exploit involves DLL injection via a proxy DLL to execute arbitrary code in the context of a PyInstaller-packaged application.

Description

In PyInstaller before version 3.6, only on Windows, a local privilege escalation vulnerability is present in this particular case: If a software using PyInstaller in "onefile" mode is launched by a privileged user (at least more than the current one) which have his "TempPath" resolving to a world writable directory. This is the case for example if the software is launched as a service or as a scheduled task using a system account (TempPath will be C:\Windows\Temp). In order to be exploitable the software has to be (re)started after the attacker launch the exploit program, so for a service launched at startup, a service restart is needed (e.g. after a crash or an upgrade).

Exploits (2)

nomisec WORKING POC 1 stars
by AlterSolutions · poc
https://github.com/AlterSolutions/PyInstallerPrivEsc

This repository contains a functional exploit for CVE-2019-16784, a PyInstaller privilege escalation vulnerability. The exploit involves DLL injection via a proxy DLL to execute arbitrary code in the context of a PyInstaller-packaged application.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Moderate
Reliability
Reliable
Target: PyInstaller (versions affected by CVE-2019-16784)
No auth needed
Prerequisites: Access to a PyInstaller-packaged application running with higher privileges · Ability to write files to the target system's temp directory
devstral-2 · analyzed Feb 18, 2026 Full analysis →
nomisec WORKING POC
by Ckrielle · poc
https://github.com/Ckrielle/CVE-2019-16784-POC

This repository contains a functional proof-of-concept exploit for CVE-2019-16784, which leverages DLL hijacking in PyInstaller's `--onefile` mode to achieve command execution and potential local privilege escalation (LPE). The exploit targets a weak directory creation mechanism in PyInstaller versions < 3.6, allowing an attacker to place a malicious DLL in the predictable `C:\Windows\Temp\_MEI*PIDX*` directory.

Classification
Working Poc 95%
Attack Type
Lpe
Complexity
Moderate
Reliability
Reliable
Target: PyInstaller < 3.6
No auth needed
Prerequisites: PyInstaller < 3.6 installed on the target system · Ability to write to `C:\Windows\Temp`
MITRE ATT&CK
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 7.0
EPSS 0.0322
EPSS Percentile 87.4%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-250 CWE-732
Status published
Products (2)
pyinstaller/pyinstaller < 3.6
pypi/PyInstaller 0 - 3.6PyPI
Published Jan 14, 2020
Tracked Since Feb 18, 2026