sshnet SSH.NET prior 2026.0.0 ScpClient os command injection

Summaryinfo

A vulnerability has been found in sshnet SSH.NET and classified as critical. Affected is an unknown function of the component ScpClient. The manipulation leads to os command injection. This vulnerability is documented as CVE-2026-85756. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in sshnet SSH.NET and classified as critical. This issue affects an unknown part of the component ScpClient. The manipulation with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-85756 since 09/04/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

Upgrading to version 2026.0.0 eliminates this vulnerability.

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Productinfo

Type

• SSH Server Software

Vendor

• sshnet

Name

• SSH.NET

Website

• Product: https://github.com/sshnet/SSH.NET/

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