Unauthenticated file write via unsanitized upload path
Published Apr 6, 2026 · Updated Apr 6, 2026
Path traversal in goshs before 2.0.0-beta.3 allows remote attackers to write arbitrary files through multipart POST uploads. In httpserver/updown.go, the POST upload handler strips path separators from the multipart filename but concatenates the unsanitized request path into finalPath, allowing dot-dot segments to escape the configured upload folder. The default configuration requires no authentication or flags, and a crafted /../../target_dir/upload path can overwrite a chosen filename in any existing directory writable by the goshs process.
Summary
What happened
Path traversal in goshs before 2.0.0-beta.3 allows remote attackers to write arbitrary files through multipart POST uploads. In httpserver/updown.go, the POST upload handler strips path separators from the multipart filename but concatenates the unsanitized request path into finalPath, allowing dot-dot segments to escape the configured upload folder. The default configuration requires no authentication or flags, and a crafted /../../target_dir/upload path can overwrite a chosen filename in any existing directory writable by the goshs process.
The record
- CVE
- CVE-2026-35393
- Published
- Apr 6, 2026
- Updated
- Apr 6, 2026
- Vendor
- Patrick Hener
- Product
- goshs
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 6, 2026CVE publishedPublication date reported by the CVE source.
- Apr 6, 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=< 2.0.0-beta.3
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
- Multipart upload path-traversal proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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