Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

CVE-2026-48798SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames

High 7.1

In plain English

A high-severity path traversal in SSH.NET from sshnet. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.4%top 63.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
NuGet	ssh.net	2026.0.0	GHSA-q939-rpr3-3284

Affected products (as reported)

Vendor	Product	Versions
sshnet	SSH.NET	< 2026.0.0

Weakness: CWE-22, CWE-73 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L

References

https://github.com/sshnet/SSH.NET/security/advisories/GHSA-q939-rpr3-3284 x_refsource_CONFIRM
https://github.com/sshnet/SSH.NET/commit/600be0de543765995a189b5d7cd4efac5007f3ce x_refsource_MISC
https://github.com/sshnet/SSH.NET/releases/tag/2026.0.0 x_refsource_MISC