CVE-2026-85756 SSH.NET: ScpClient allows server-side RCE via default SCP path handling
Attacker-controlled paths in SSH.NET ScpClient can execute commands on shell-based servers due to insufficient quoting, requiring an upgrade to fix.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-85756?
CVE-2026-85756 is a high-severity command injection vulnerability in sshnet SSH.NET, published on 16 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-78
Which versions are affected by CVE-2026-85756?
2 open source packages ship an affected version, including SSH.NET.
| Package | Affected | Fixed in |
|---|---|---|
SSH.NET NuGet | All versions | 2026.0.0 |
SSH.NET NuGet | All versions | 2026.0.0 |
How do I fix CVE-2026-85756?
Upgrade SSH.NET to 2026.0.0 or later.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-85756 being exploited?
There is no known exploitation of CVE-2026-85756 in the wild and no public exploit code.
Sources
Also known as GHSA-mggc-4xg6-vcxf.