CVE-2026-33430Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions
- 7.3HighCVSS base score
- 0.14%Exploitation in 30 daysEPSS · top 97% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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
ID reserved
By GitHub_M
- 7 days later
· 7 days later
Published
- 6 days later
· 6 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High7.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.14% · top 97% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.3.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIbriefcaseGHSA-r3r2-35v9-v238 (opens in a new tab)
References
References4
- https://github.com/beeware/briefcase/security/advisories/GHSA-r3r2-35v9-v238 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/beeware/briefcase/issues/2759 (opens in a new tab)x_refsource_MISC
- https://github.com/beeware/briefcase-windows-VisualStudio-template/pull/85 (opens in a new tab)x_refsource_MISC
- https://github.com/beeware/briefcase-windows-app-template/pull/86 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-16260 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-r3r2-35v9-v238 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-33430)Record last updated .