CVE-2026-48798 SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames
A malicious SSH server can exploit path traversal in SSH.NET's SCP client to write arbitrary files on the client system, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48798?
CVE-2026-48798 is a high-severity path traversal vulnerability in sshnet SSH.NET, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
SSH.NET is a Secure Shell (SSH) library for .NET. In 2025.1.0 and earlier, ScpClient.Download(string directoryName, DirectoryInfo directoryInfo) trusts file and directory names returned by a remote SCP server and combines them with the requested local directory without containment validation, allowing a malicious, compromised, or man-in-the-middle server to use ../ sequences or absolute paths to create or overwrite files anywhere writable by the client process. This issue is fixed in version 2026.0.0.
Which versions are affected by CVE-2026-48798?
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-2026-48798?
Upgrade SSH.NET to 2026.0.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-48798 being exploited?
There is no known exploitation of CVE-2026-48798 in the wild and no public exploit code.
Sources
Also known as GHSA-q939-rpr3-3284.