Path Traversal in SSH.NET (CVE-2026-48798)
Summary
Path traversal in SSH.NET (CVE-2026-48798). Data can be tampered with by attackers. Exploitable via ScpException. Mitigation: upgrade to 2026.0.0 or later.
Original description
The description as published by the source.
Summary
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, but with directory traversal capability.
Impact
A 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.
Remediation
The 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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-48798 has been found in SSH.NET.
Attackers can target a specific entry point like ScpException over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.1/10.
What to do: upgrade SSH.NET to 2026.0.0 or later.
If unsure, ask your IT team or search "SSH.NET CVE-2026-48798" on the vendor's site.
CVE-2026-48798 (SSH.NET) — CWE-22 / CVSS v3 7.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: ScpException
Patched: 2026.0.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in SSH.NET. Attackers reach the vulnerable code path via ScpException without authentication.
Check the vendor advisory for the affected versions of SSH.NET. Attack surface: ScpException.
Severity: High (CVSS 7.1/10). Data can be tampered with by attackers.
Update to 2026.0.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'SSH.NET' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'SSH.NET' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
SSH.NETを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade SSH.NET to 2026.0.0ステージング環境で 2026.0.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com