CVE-2026-50558 Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive
A malicious session can write files outside the download directory, potentially overwriting configuration files to escalate privileges or modify data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-50558?
CVE-2026-50558 is a medium-severity path traversal vulnerability in brightio penelope, published on 29 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-22
Which versions are affected by CVE-2026-50558?
3 open source packages ship an affected version, including penelope-shell-handler.
| Package | Affected | Fixed in |
|---|---|---|
penelope-shell-handler PyPI | All versions | 0.20.0 |
penelope-shell-handler PyPI | All versions | 0.20.0 |
penelope-shell-handler PyPI | All versions | 0.20.0 |
How do I fix CVE-2026-50558?
Upgrade penelope-shell-handler to 0.20.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-50558 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-50558 exists.
Sources
Also known as GHSA-f42x-p2mx-hm8r, PYSEC-2026-3606.