{"id":"CVE-2026-33430","aliases":["EUVD-2026-16260","GHSA-r3r2-35v9-v238","PYSEC-2026-27"],"status":"published","title":"Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions","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.","severity":{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00137,"percentile":0.03196,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-732"],"published":"2026-03-23T21:40:10Z","modified":"2026-10-28T02:31:08Z","fixes":[{"ecosystem":"PyPI","package":"briefcase","fixed_in":["0.3.26"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"briefcase","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.0"},{"fixed":"0.3.26"}]}]},{"source":"osv","ecosystem":"PyPI","package":"briefcase","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.0"},{"fixed":"0.3.26"}]}],"versions":["0.3.0","0.3.1","0.3.10","0.3.10rc7","0.3.10rc8","0.3.11","0.3.11rc4","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26rc5","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9"]},{"source":"osv","ecosystem":"PyPI","package":"briefcase","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.0"},{"fixed":"0.3.26"}]}],"versions":["0.3.0","0.3.1","0.3.10","0.3.10rc7","0.3.10rc8","0.3.11","0.3.11rc4","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26rc5","0.3.3","0.3.4","0.3.5","0.3.6","0.3.7","0.3.8","0.3.9"]}],"products":[{"vendor":"beeware","product":"briefcase"}],"references":[{"url":"https://github.com/beeware/briefcase/security/advisories/GHSA-r3r2-35v9-v238","tags":["x_refsource_CONFIRM","Mitigation","Patch","Vendor Advisory","advisory","web","fix"]},{"url":"https://github.com/beeware/briefcase/issues/2759","tags":["x_refsource_MISC","Issue Tracking","report","web"]},{"url":"https://github.com/beeware/briefcase-windows-VisualStudio-template/pull/85","tags":["x_refsource_MISC","Issue Tracking","Patch","fix","web"]},{"url":"https://github.com/beeware/briefcase-windows-app-template/pull/86","tags":["x_refsource_MISC","Issue Tracking","Patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33430","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/briefcase/PYSEC-2026-27.yaml","tags":["web"]},{"url":"https://github.com/advisories/GHSA-r3r2-35v9-v238"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33430.json","tags":["advisory"]},{"url":"https://github.com/beeware/briefcase","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-33430","title":"Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions","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.","status":"published","published":"2026-03-26T16:54:42.992Z","modified":"2026-04-01T03:55:18.727Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T14:20:08.009733Z"}],"euvd":[{"id":"EUVD-2026-16260","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.","status":"published","published":"2026-03-26T16:54:42Z","modified":"2026-04-01T03:55:18Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T19:25:24.493801Z"}],"ghsa":[{"id":"GHSA-r3r2-35v9-v238","title":"Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions ","description":"### Impact\n\nIf 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.\n\n### Patches\n\nThe problem is caused by the template used to generate the WXS file for Windows projects. It was fixed with the following PRs:\n\n* beeware/briefcase-windows-app-template#86\n* beeware/briefcase-windows-VisualStudio-template#85\n\nThese patches have been backported to 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.\n\n### Workarounds\n\nThe change from beeware/briefcase-windows-app-template#86 can be added to any existing Briefcase .wxs file generated by Briefcase 0.3.24 or later.\n\n### Resources\n\nbeeware/briefcase#2759 is a formal bug report of the problem.","status":"published","published":"2026-03-23T21:40:10Z","modified":"2026-06-05T14:26:49Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T14:40:16.698699Z"}],"nvd":[{"id":"CVE-2026-33430","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.","status":"published","published":"2026-03-26T17:16:38.713Z","modified":"2026-06-17T10:37:29.233Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T14:12:11.678711Z"}],"osv":[{"id":"CVE-2026-33430","title":"Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions","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.","status":"published","published":"2026-03-26T16:54:42.992Z","modified":"2026-10-28T02:31:08.257034927Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"GHSA-r3r2-35v9-v238","title":"Briefcase: Windows MSI Installer Privilege Escalation via Insecure Directory Permissions ","description":"### Impact\n\nIf 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.\n\n### Patches\n\nThe problem is caused by the template used to generate the WXS file for Windows projects. It was fixed with the following PRs:\n\n* beeware/briefcase-windows-app-template#86\n* beeware/briefcase-windows-VisualStudio-template#85\n\nThese patches have been backported to 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.\n\n### Workarounds\n\nThe change from beeware/briefcase-windows-app-template#86 can be added to any existing Briefcase .wxs file generated by Briefcase 0.3.24 or later.\n\n### Resources\n\nbeeware/briefcase#2759 is a formal bug report of the problem.","status":"published","published":"2026-03-23T21:40:10Z","modified":"2026-06-05T14:30:11.172961403Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-732"],"updated_at":"2026-11-02T15:46:55.122811Z"},{"id":"PYSEC-2026-27","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.","status":"published","published":"2026-03-26T17:16:38.713Z","modified":"2026-05-20T09:18:53.838122Z","cvss":[{"version":"3.1","score":7.3,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:52:55.961245Z"}]}}