CVE-2026-85756

HighCVSS 7.5

Published: 16/09/2026(UTC)Updated: 30/09/2026(UTC)Translated: 16/09/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.62%

48th percentile - higher than 48% of all known CVEs

Summary

SSH.NET prior to 2026.0.0 has ScpClient placing caller-supplied remote paths into the scp command, and the default RemotePathTransformation.DoubleQuote cannot safely quote every remote command interpreter. When an application passes an attacker-controlled path to a shell-based server, shell metacharacters can execute commands as the authenticated SSH user.

Risk Assessment

An attacker could execute arbitrary commands on the SSH server with the privileges of the authenticated user, potentially leading to system compromise. Only shell-based servers and specially crafted paths are affected.

Recommendation

Upgrade SSH.NET to version 2026.0.0 or later. For POSIX shells, use RemotePathTransformation.ShellQuote, and where possible use SftpClient, which avoids a remote shell entirely.

Other vulnerabilities in SSH.NET

CVE-2026-48798High
SSH.NET, an SSH library for .NET, has a vulnerability in ScpClient.Download that trusts file and directory names returned by a remote SCP server. A malicious or compromised server can use ../ sequences or absolute paths to create or overwrite files anywhere writable by the client process. The issue is fixed in version 2026.0.0.

Original NVD description (English source)

SSH.NET is a Secure Shell (SSH) library for .NET. Prior to 2026.0.0, ScpClient places caller-supplied remote paths into the command used to run scp on the server, and the default RemotePathTransformation.DoubleQuote transformation cannot safely quote every remote command interpreter. When an application passes an attacker-controlled path to a shell-based server, shell metacharacters not neutralized by the active IRemotePathTransformation can execute commands as the authenticated SSH user. Exploitation requires a shell-based server and a path crafted for that shell's parsing rules; non-shell servers and paths fully neutralized by the selected transformation are not affected. RemotePathTransformation.ShellQuote is available for POSIX shells, while SftpClient avoids a remote shell entirely. This issue is fixed in version 2026.0.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS