{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.23.1"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1b5839f3827f7bf546fc311cc8da77788a9d22f7"
            }
          ],
          "repo": "https://github.com/ronf/asyncssh",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qr67-gv47-xwwh"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-22",
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54590.json"
  },
  "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": "CVE-2026-54590",
  "modified": "2026-08-04T11:30:56.054478855Z",
  "published": "2026-07-08T20:36:45.258Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ronf/asyncssh/releases/tag/v2.23.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54590.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54590"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "AsyncSSH AuthorizedKeysFile username substitution bypass through ~ and environment expansion"
}