{"id":"CVE-2026-48798","aliases":["EUVD-2026-60945","GHSA-q939-rpr3-3284"],"status":"published","title":"SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames","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.","severity":{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00421,"percentile":0.36699,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-22","CWE-73"],"published":"2026-08-12T15:19:10Z","modified":"2026-10-28T02:30:23Z","fixes":[{"ecosystem":"NuGet","package":"SSH.NET","fixed_in":["2026.0.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"NuGet","package":"SSH.NET","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2025.1.0"},{"fixed":"2026.0.0"}]}]},{"source":"osv","ecosystem":"NuGet","package":"SSH.NET","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2026.0.0"}]}],"versions":["2011.12.7","2011.7.29","2011.9.28","2012.12.3","2012.20.12","2012.21.12","2012.3.9","2013.1.27","2013.1.8","2013.4.7","2014.4.6-beta1","2014.4.6-beta2","2016.0.0","2016.0.0-beta1","2016.0.0-beta2","2016.0.0-beta3","2016.1.0","2016.1.0-beta1","2016.1.0-beta2","2016.1.0-beta3","2016.1.0-beta4","2020.0.0","2020.0.0-beta1","2020.0.1","2020.0.2","2023.0.0","2023.0.1","2024.0.0","2024.1.0","2024.2.0","2025.0.0","2025.1.0"]}],"products":[{"vendor":"sshnet","product":"ssh.net"}],"references":[{"url":"https://github.com/sshnet/SSH.NET/security/advisories/GHSA-q939-rpr3-3284","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/sshnet/SSH.NET/commit/600be0de543765995a189b5d7cd4efac5007f3ce","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/sshnet/SSH.NET/releases/tag/2026.0.0","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48798","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-q939-rpr3-3284"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48798.json","tags":["advisory"]},{"url":"https://github.com/sshnet/SSH.NET","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-48798","title":"SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames","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.","status":"published","published":"2026-08-18T14:57:05.059Z","modified":"2026-08-18T15:28:45.711Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high","assessor":"cna"}],"cwes":["CWE-22","CWE-73"],"updated_at":"2026-11-02T13:50:49.872037Z"}],"euvd":[{"id":"EUVD-2026-60945","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.","status":"published","published":"2026-08-18T14:57:05Z","modified":"2026-08-18T15:28:45Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high"}],"updated_at":"2026-11-02T18:01:46.405062Z"}],"ghsa":[{"id":"GHSA-q939-rpr3-3284","title":"SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames","description":"## Summary\n\n`ScpClient.Download(string directoryName, DirectoryInfo directoryInfo)` writes files and directories using names returned by the remote SCP server during recursive downloads, with no validation that the resulting path stays inside the requested local directory. A malicious, compromised, or man-in-the-middle SCP server can return names containing `../` sequences (or absolute paths), causing the client to create directories and write/overwrite files anywhere the client process has access. This is similar to OpenSSH [CVE-2019-6111](https://github.com/advisories/GHSA-jr78-hfw4-xp7g), but with directory traversal capability.\n\n## Impact\n\nA malicious/compromised/MITM SCP server can create or write files outside the intended download directory, anywhere the client process can write. Overwriting files such as ~/.ssh/authorized_keys, shell rc files, cron entries, or application binaries/config can lead to persistence, privilege escalation, or remote code execution on the client host. Requires the victim to perform a directory download from the attacker-controlled server.\n\n## Remediation\n\nThe fixed release ensures that remotely-supplied file and directory names are valid local names such that the constructed local path is contained within the given local directory, and throws `ScpException` when an invalid name is detected.\n\n[600be0de543765995a189b5d7cd4efac5007f3ce](https://github.com/sshnet/SSH.NET/commit/600be0de543765995a189b5d7cd4efac5007f3ce)","status":"published","published":"2026-08-12T15:19:10Z","modified":"2026-08-18T18:05:09Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-22","CWE-73"],"updated_at":"2026-11-02T14:41:03.602876Z"}],"nvd":[{"id":"CVE-2026-48798","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.","status":"published","published":"2026-08-18T15:16:54.427Z","modified":"2026-10-22T22:10:00.25Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high","assessor":"secondary"}],"cwes":["CWE-22","CWE-73"],"updated_at":"2026-11-02T14:12:38.976695Z"}],"osv":[{"id":"CVE-2026-48798","title":"SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames","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.","status":"published","published":"2026-08-18T14:57:05.059Z","modified":"2026-10-28T02:30:23.545438774Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-22","CWE-73"],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"GHSA-q939-rpr3-3284","title":"SSH.NET: ScpClient Recursive Download Allows Arbitrary File Write via Server-Controlled SCP Filenames","description":"## Summary\n\n`ScpClient.Download(string directoryName, DirectoryInfo directoryInfo)` writes files and directories using names returned by the remote SCP server during recursive downloads, with no validation that the resulting path stays inside the requested local directory. A malicious, compromised, or man-in-the-middle SCP server can return names containing `../` sequences (or absolute paths), causing the client to create directories and write/overwrite files anywhere the client process has access. This is similar to OpenSSH [CVE-2019-6111](https://github.com/advisories/GHSA-jr78-hfw4-xp7g), but with directory traversal capability.\n\n## Impact\n\nA malicious/compromised/MITM SCP server can create or write files outside the intended download directory, anywhere the client process can write. Overwriting files such as ~/.ssh/authorized_keys, shell rc files, cron entries, or application binaries/config can lead to persistence, privilege escalation, or remote code execution on the client host. Requires the victim to perform a directory download from the attacker-controlled server.\n\n## Remediation\n\nThe fixed release ensures that remotely-supplied file and directory names are valid local names such that the constructed local path is contained within the given local directory, and throws `ScpException` when an invalid name is detected.\n\n[600be0de543765995a189b5d7cd4efac5007f3ce](https://github.com/sshnet/SSH.NET/commit/600be0de543765995a189b5d7cd4efac5007f3ce)","status":"published","published":"2026-08-12T15:19:10Z","modified":"2026-08-18T18:15:08.423630427Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-22","CWE-73"],"updated_at":"2026-11-02T15:46:54.40888Z"}]}}