TI-2026-37280 Aliases CVE-2026-50558 GHSA-f42x-p2mx-hm8r

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

MEDIUM 60CWE-22Published 2026-07-29 · Updated 2026-07-29

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: High
Impact type: —
Confidentiality · integrity · availability: None · High · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00367 30th percentileScored 2026-11-07

Fix Fixed penelope (brightio): 0.20.0penelope-shell-handler (PyPI): 0.20.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
brightio	penelope	before 0.20.0	0.20.0	Patch available	CNA
—	penelope-shell-handler (PyPI)	before 0.20.0	0.20.0	Patch available	GHSA-f42x-p2mx-hm8r

penelope Vendorbrightio Affected before 0.20.0 Fixed in 0.20.0 Patch available CNA
penelope-shell-handler (PyPI) Vendor— Affected before 0.20.0 Fixed in 0.20.0 Patch available GHSA-f42x-p2mx-hm8r

Remediation

Fix · CNA penelope (brightio) Fixed in 0.20.0
Fix · GHSA-f42x-p2mx-hm8r penelope-shell-handler (PyPI) Fixed in 0.20.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-50558
2026-10-03 Alias added: GHSA-f42x-p2mx-hm8r

References

Other 4

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences