PyInstaller has local privilege escalation vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.0 · CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-59042: 0.13% estimated exploitation activity in the next 30 days; percentile 2.29 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Due to a special entry being appended to sys.path during the bootstrap process of a PyInstaller-frozen application, and due to the bootstrap script attempting to load an optional module for bytecode decryption while this entry is still present in sys.path, an application built with PyInstaller < 6.0.0 may be tricked by an unprivileged attacker into executing arbitrary python code when all of the following conditions are met: 1. Application is built with PyInstaller < 6.0.0; both onedir and onefile mode are affected. 2. Optional bytecode encryption code feature was not enabled during the application build. 3. The attacker can create files/directories in the same directory where the executable is located. 4. The filesystem supports creation of files/directories that contain ? in their name (i.e., non-Windows systems). 5. The attacker is able to determine the offset at which the PYZ archive is embedded in the executable. The attacker can create a directory (or a zip archive) next…

Published by the source

10 Sep 2025, 20:30 UTC

Last modified by the source

7 Jul 2026, 17:57 UTC

Source last checked

26 Oct 2026, 13:35 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-p2xp-xx3r-mffc

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-p2xp-xx3r-mffc

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# Patch Next advisory brief: CVE-2025-59042

Advisory: PyInstaller has local privilege escalation vulnerability
IDs: CVE-2025-59042, GHSA-p2xp-xx3r-mffc
Record: https://patchnext.com/advisories/cve-2025-59042 (revision 3, source checked 26 Oct 2026, 13:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pyinstaller 6.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pyinstaller: affected < 6.0.0; fixed in 6.0.0

## Suggested inspection (read-only)
- `python -m pip show pyinstaller`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pyinstaller.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-p2xp-xx3r-mffc (OSV record GHSA-p2xp-xx3r-mffc lists affected ranges: PyPI pyinstaller >=0 <6.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-p2xp-xx3r-mffc (GitHub-reviewed advisory GHSA-p2xp-xx3r-mffc lists affected ranges: PyPI pyinstaller >=0 <6.0.0)

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