{"id":"CVE-2022-29245","aliases":["EUVD-2022-5968","GHSA-72p8-v4hg-v45p"],"status":"published","title":"Weak private key generation in SSH.NET","description":"SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.01478,"percentile":0.74075,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-330","CWE-338"],"published":"2022-05-31T16:35:11Z","modified":"2026-10-28T02:30:59Z","fixes":[{"ecosystem":"NuGet","package":"SSH.NET","fixed_in":["2020.0.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"NuGet","package":"SSH.NET","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2020.0.2"}]}]},{"source":"osv","ecosystem":"NuGet","package":"SSH.NET","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2020.0.2"}]}],"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"]}],"products":[{"vendor":"ssh.net_project","product":"ssh.net"},{"vendor":"sshnet","product":"ssh.net"}],"references":[{"url":"https://github.com/sshnet/SSH.NET/security/advisories/GHSA-72p8-v4hg-v45p","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Mitigation","Third Party Advisory","advisory","web"]},{"url":"https://github.com/sshnet/SSH.NET/commit/03c6d60736b8f7b42e44d6989a53f9b644a091fb","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/sshnet/SSH.NET/blob/bc99ada7da3f05f50d9379f2644941d91d5bf05a/src/Renci.SshNet/Security/KeyExchangeECCurve25519.cs#L51","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","web"]},{"url":"https://github.com/sshnet/SSH.NET/releases/tag/2020.0.2","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2022-29245","tags":["advisory"]},{"url":"https://github.com/sshnet/SSH.NET/commit/f1f273cf349532b9d41c1de51d3b83a9accedc88","tags":["web"]},{"url":"https://github.com/advisories/GHSA-72p8-v4hg-v45p"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/29xxx/CVE-2022-29245.json","tags":["advisory"]},{"url":"https://github.com/sshnet/SSH.NET","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2022-29245","title":"Weak private key generation in SSH.NET","description":"SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms.","status":"published","published":"2022-05-31T16:35:11Z","modified":"2025-04-22T17:55:45.721Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T14:34:36.270817Z"}],"euvd":[{"id":"EUVD-2022-5968","description":"SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms.","status":"published","published":"2022-05-31T16:35:11Z","modified":"2025-04-22T17:55:45Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T20:52:15.540112Z"}],"ghsa":[{"id":"GHSA-72p8-v4hg-v45p","title":"Weak private key generation in SSH.NET","description":"During an **X25519** key exchange, the client’s private is generated with [**System.Random**](https://docs.microsoft.com/en-us/dotnet/api/system.random):\n\n```cs\nvar rnd = new Random();\n_privateKey = new byte[MontgomeryCurve25519.PrivateKeySizeInBytes];\nrnd.NextBytes(_privateKey);\n```\n\nSource: [KeyExchangeECCurve25519.cs](https://github.com/sshnet/SSH.NET/blob/bc99ada7da3f05f50d9379f2644941d91d5bf05a/src/Renci.SshNet/Security/KeyExchangeECCurve25519.cs#L51)  \nSource commit: https://github.com/sshnet/SSH.NET/commit/b58a11c0da55da1f5bad46faad2e9b71b7cb35b3\n\n[**System.Random**](https://docs.microsoft.com/en-us/dotnet/api/system.random) is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes.\n\n### Impact\nWhen establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with\na weak random number generator whose seed can be bruteforced. This allows an attacker able to eavesdrop the\ncommunications to decrypt them.\n\n### Workarounds\nTo ensure you're not affected by this vulnerability, you can disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms by invoking the following method before a connection is established:\n```cs\nprivate static void RemoveUnsecureKEX(BaseClient client)\n{\n    client.ConnectionInfo.KeyExchangeAlgorithms.Remove(\"curve25519-sha256\");\n    client.ConnectionInfo.KeyExchangeAlgorithms.Remove(\"curve25519-sha256@libssh.org\");\n}\n```\n\n### Thanks\n\nThis issue was initially reported by **Siemens AG, Digital Industries**, shortly followed by @yaumn-synacktiv.","status":"published","published":"2022-06-01T19:50:15Z","modified":"2023-01-27T05:03:19Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-330","CWE-338"],"updated_at":"2026-11-02T14:36:20.144464Z"}],"nvd":[{"id":"CVE-2022-29245","description":"SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms.","status":"published","published":"2022-05-31T17:15:07.837Z","modified":"2026-06-17T04:39:54.52Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T14:07:21.261605Z"}],"osv":[{"id":"CVE-2022-29245","title":"Weak private key generation in SSH.NET","description":"SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms.","status":"published","published":"2022-05-31T16:35:11Z","modified":"2026-10-28T02:30:59.652147905Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-338"],"updated_at":"2026-11-02T15:44:25.164673Z"},{"id":"GHSA-72p8-v4hg-v45p","title":"Weak private key generation in SSH.NET","description":"During an **X25519** key exchange, the client’s private is generated with [**System.Random**](https://docs.microsoft.com/en-us/dotnet/api/system.random):\n\n```cs\nvar rnd = new Random();\n_privateKey = new byte[MontgomeryCurve25519.PrivateKeySizeInBytes];\nrnd.NextBytes(_privateKey);\n```\n\nSource: [KeyExchangeECCurve25519.cs](https://github.com/sshnet/SSH.NET/blob/bc99ada7da3f05f50d9379f2644941d91d5bf05a/src/Renci.SshNet/Security/KeyExchangeECCurve25519.cs#L51)  \nSource commit: https://github.com/sshnet/SSH.NET/commit/b58a11c0da55da1f5bad46faad2e9b71b7cb35b3\n\n[**System.Random**](https://docs.microsoft.com/en-us/dotnet/api/system.random) is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes.\n\n### Impact\nWhen establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with\na weak random number generator whose seed can be bruteforced. This allows an attacker able to eavesdrop the\ncommunications to decrypt them.\n\n### Workarounds\nTo ensure you're not affected by this vulnerability, you can disable support for `curve25519-sha256` and `curve25519-sha256@libssh.org` key exchange algorithms by invoking the following method before a connection is established:\n```cs\nprivate static void RemoveUnsecureKEX(BaseClient client)\n{\n    client.ConnectionInfo.KeyExchangeAlgorithms.Remove(\"curve25519-sha256\");\n    client.ConnectionInfo.KeyExchangeAlgorithms.Remove(\"curve25519-sha256@libssh.org\");\n}\n```\n\n### Thanks\n\nThis issue was initially reported by **Siemens AG, Digital Industries**, shortly followed by @yaumn-synacktiv.","status":"published","published":"2022-06-01T19:50:15Z","modified":"2023-11-08T04:09:12.044025Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-330","CWE-338"],"updated_at":"2026-11-02T15:46:40.308826Z"}]}}