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CVE-2026-33430GHSA-R3R2-35V9-V238PYSEC-2026-27

Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.3.26
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

Briefcase is a tool for converting a Python project into a standalone native application. Starting in version 0.3.0 and prior to version 0.3.26, if a developer uses Briefcase to produce an Windows MSI installer for a project, and that project is installed for All Users (i.e., per-machine scope), the installation process creates an directory that inherits all the permissions of the parent directory. Depending on the location chosen by the installing user, this may allow a low privilege but authenticated user to replace or modify the binaries installed by the application. If an administrator then runs the altered binary, the binary will run with elevated privileges. The problem is caused by the template used to generate the WXS file for Windows projects. It was fixed in the templates used in Briefcase 0.3.26, 0.4.0, and 0.4.1. Re-running `briefcase create` on your Briefcase project will result in the updated templates being used. As a workaround, the patch can be added to any existing Briefcase .wxs file generated by Briefcase 0.3.24 or later.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • beeware briefcase

    From 0.3.0 · fixed in 0.3.26

  • briefcasePyPI

    From 0.3.0 · fixed in 0.3.26

References 4

GitHub · beeware/briefcase

GitHub · beeware/briefcase-windows-VisualStudio-template

GitHub · beeware/briefcase-windows-app-template