CVE-2026-50558
MEDIUMCVE-2026-50558 is a medium-severity (CVSS 5.9) Path Traversal vulnerability in penelope-shell-handler. O3 Security confirms whether CVE-2026-50558 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive
Blast Radius
penelope-shell-handlerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Penelope Shell Handler is a post-exploitation shell handler for authorized security testing. Prior to 0.20.0, the Unix download() implementation in penelope.py used tar.extractall(local_download_folder) on tar archives returned by remote sessions without validating member paths, allowing a malicious or compromised session to write files outside the intended download directory and potentially overwrite ~/.penelope/peneloperc. This issue is fixed in version 0.20.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | penelope-shell-handler | all versions | 0.20.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for penelope-shell-handler. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update penelope-shell-handler to 0.20.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50558 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-50558 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-50558. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-50558 in your dependencies?
O3 detects CVE-2026-50558 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.