Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive

Exploitation

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

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L

EPSS

• CVE-2026-50558: 0.37% estimated exploitation activity in the next 30 days; percentile 30.62 (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.

Summary Penelope versions prior to 0.19.3 extracted tar archives received from remote sessions without validating archive member paths. When using the affected Unix download path, a malicious or compromised remote session could return a crafted tar archive containing path traversal entries, such as ../, causing files to be written outside the intended download directory on the Penelope operator's machine. The impact is limited to files writable by the user running Penelope. In some cases, this arbitrary file write could be chained to operator-side code execution if the attacker can overwrite a file that Penelope or the user later executes, such as ~/.penelope/peneloperc. The issue has been fixed in version 0.19.3 by rejecting unsafe archive paths during extraction. Affected conditions The issue requires the operator to use the Main Menu download command to download files from a malicious or compromised remote session that can influence the tar archive returned to Penelope. The Python…

Published by the source

29 Jul 2026, 15:34 UTC

Last modified by the source

29 Jul 2026, 15:34 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-f42x-p2mx-hm8r

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# Patch Next advisory brief: CVE-2026-50558

Advisory: Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive
IDs: CVE-2026-50558, GHSA-f42x-p2mx-hm8r
Record: https://patchnext.com/advisories/cve-2026-50558 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: penelope-shell-handler 0.20.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI penelope-shell-handler: affected < 0.20.0; fixed in 0.20.0

## Suggested inspection (read-only)
- `python -m pip show penelope-shell-handler`: 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 penelope-shell-handler.
- 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://github.com/advisories/GHSA-f42x-p2mx-hm8r (GitHub-reviewed advisory GHSA-f42x-p2mx-hm8r lists affected ranges: PyPI penelope-shell-handler >=0 <0.20.0)

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