Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/sshnet/SSH.NET/commit/c66b9f8fb06c12e71761e58a577b1e796026310
- https://github.com/sshnet/SSH.NET/releases/tag/2026.0.0
- https://github.com/sshnet/SSH.NET/security/advisories/GHSA-mggc-4xg6-vcxf
FAQ
What is CVE-2026-85756?
CVE-2026-85756 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 RemotePathTransformat...
How severe is CVE-2026-85756?
CVE-2026-85756 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-85756?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.