CVE-2026-50558 json
Penelope unsafe tar extraction allows arbitrary local file write via crafted session archive
published 2026-07-29 3 mo ago modified 2026-10-23 16 d ago also GHSA-f42x-p2mx-hm8r , PYSEC-2026-3606 , EUVD-2026-50395
- cvss
- 5.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
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.
Patch / fix
- pypi penelope-shell-handler 0.20.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/brightio/penelope/security/advisories/GHSA-f42x-p2mx-hm8r referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L |
| OSV | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L |
| GitHub | 3.1 | 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | penelope-shell-handler | <0.20.0 |
0.20.0 |
Affected products
- brightio penelope
Classification
- Weakness
-
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory
References
-
github.com
/brightio/penelope/commit/a040afb5db32c7e80b5e8a2f9b2164cf911cfa62
web
-
github.com
/brightio/penelope/security/advisories/GHSA-f42x-p2mx-hm8r
exploit, web
-
github.com
/brightio/penelope/releases/tag/v0.20.0
web
-
github.com
/brightio/penelope
package
-
pypi.org
/project/penelope-shell-handler
package
-
github.com
/advisories/GHSA-f42x-p2mx-hm8r
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-50558
advisory
Sources
- CVE List CVE-2026-50558
- GitHub Advisory GHSA-f42x-p2mx-hm8r
- NVD CVE-2026-50558
- OSV PYSEC-2026-3606
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.