Arbitrary file write via unchecked archive paths
Published Jul 29, 2026 · Updated Jul 29, 2026
Path traversal in Penelope Shell Handler before 0.19.3 allows remote attackers to write files through a crafted session archive. The Unix download() path passes untrusted tar members to extractall() without confirming that their resolved destinations remain under the download directory. Exploitation requires an operator to invoke the Main Menu download command against a malicious or compromised session; writes are limited to operator-writable paths and can lead to code execution when an overwritten startup file is later loaded.
Summary
What happened
Path traversal in Penelope Shell Handler before 0.19.3 allows remote attackers to write files through a crafted session archive. The Unix download() path passes untrusted tar members to extractall() without confirming that their resolved destinations remain under the download directory. Exploitation requires an operator to invoke the Main Menu download command against a malicious or compromised session; writes are limited to operator-writable paths and can lead to code execution when an overwritten startup file is later loaded.
The record
- CVE
- CVE-2026-50558
- Published
- Jul 29, 2026
- Updated
- Jul 29, 2026
- Vendor
- brightio
- Product
- Penelope Shell Handler
- Classifications
- CWE-22, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 29, 2026CVE publishedPublication date reported by the CVE source.
- Jul 29, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.20.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream malicious session archive proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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