ubuntu-cve-2026-54590
Vulnerability from osv_ubuntu
Published
2026-07-08 21:16
Modified
2026-07-15 17:53
Summary
Details

AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "1.3.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@1.3.0-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.2.0-1",
        "1.2.1-1",
        "1.3.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "1.11.1-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@1.11.1-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.8.1-2",
        "1.11.0-2",
        "1.11.1-1",
        "1.11.1-1ubuntu0.1~esm1",
        "1.11.1-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "1.12.2-1ubuntu0.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@1.12.2-1ubuntu0.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.12.2-1",
        "1.12.2-1ubuntu0.1",
        "1.12.2-1ubuntu0.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "2.5.0-1ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@2.5.0-1ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.5.0-1",
        "2.5.0-1ubuntu0.1~esm1",
        "2.5.0-1ubuntu0.1",
        "2.5.0-1ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "2.10.1-2ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@2.10.1-2ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.10.1-2",
        "2.10.1-2ubuntu0.1",
        "2.10.1-2ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "2.20.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@2.20.0-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.20.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-asyncssh",
            "binary_version": "2.21.1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "python-asyncssh",
        "purl": "pkg:deb/ubuntu/python-asyncssh@2.21.1-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.20.0-1",
        "2.21.1-1"
      ]
    }
  ],
  "aliases": [],
  "details": "AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.",
  "id": "UBUNTU-CVE-2026-54590",
  "modified": "2026-07-15T17:53:43Z",
  "published": "2026-07-08T21:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-54590"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-54590"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ronf/asyncssh/releases/tag/v2.23.1"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-54590"
  ]
}



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