Arbitrary file write via SCP path traversal
Published Aug 18, 2026 · Updated Aug 18, 2026
Path traversal in ScpClient in SSH.NET before 2026.0.0 allows remote attackers to overwrite local files via malicious SCP names. During recursive downloads, ScpClient.Download(string directoryName, DirectoryInfo directoryInfo) combines server-supplied C and D record names into local paths with Path.Combine and does not reject ../, absolute paths, or platform path separators before creating directories or files. Exploitation requires a victim to download a directory from a malicious, compromised, or man-in-the-middle SCP server, after which any path writable by the client process can be created or overwritten.
Summary
What happened
Path traversal in ScpClient in SSH.NET before 2026.0.0 allows remote attackers to overwrite local files via malicious SCP names. During recursive downloads, ScpClient.Download(string directoryName, DirectoryInfo directoryInfo) combines server-supplied C and D record names into local paths with Path.Combine and does not reject ../, absolute paths, or platform path separators before creating directories or files. Exploitation requires a victim to download a directory from a malicious, compromised, or man-in-the-middle SCP server, after which any path writable by the client process can be created or overwritten.
The record
- CVE
- CVE-2026-48798
- Published
- Aug 18, 2026
- Updated
- Aug 18, 2026
- Vendor
- SSH.NET
- Product
- SSH.NET
- Classifications
- CWE-73, CWE-22
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 18, 2026CVE publishedPublication date reported by the CVE source.
- Aug 18, 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=< 2026.0.0
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
- SecureLayer7 working proof of concept for CVE-2026-48798proof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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