{"id":"CVE-2026-45309","summary":"AsyncSSH `AuthorizedKeysFile %u` path traversal allows attacker-selected authorized keys to authenticate a traversal username","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. Prior to 2.23.0, AsyncSSH expands the OpenSSH-compatible AuthorizedKeysFile %u token in asyncssh/config.py, asyncssh/connection.py, asyncssh/auth_keys.py, and asyncssh/misc.py with the raw SSH username during pre-authentication server config reload, allowing a server configured with AuthorizedKeysFile authorized_keys/%u to read an authorized-keys file outside the intended directory when the SSH username contains /, \\, or .. path traversal segments and authenticate with an attacker-selected key file. This issue is fixed in version 2.23.0.","aliases":["GHSA-g794-3fmp-753h","PYSEC-2026-2384"],"modified":"2026-07-19T03:46:59.320847878Z","published":"2026-07-17T18:40:02.428Z","related":["CGA-w94f-4h34-jj3p","openSUSE-SU-2026:11042-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-22"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45309.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45309.json"},{"type":"ADVISORY","url":"https://github.com/ronf/asyncssh/security/advisories/GHSA-g794-3fmp-753h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45309"},{"type":"FIX","url":"https://github.com/ronf/asyncssh/commit/2af2382cce946c959a378a62f257af253dc4ab51"},{"type":"FIX","url":"https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ronf/asyncssh","events":[{"introduced":"0"},{"fixed":"2af2382cce946c959a378a62f257af253dc4ab51"},{"fixed":"3d515ba9ba0cd9990d248bdf62bcf05d51261a88"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.23.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v2.23.0","v2.22.0","v2.21.1","v2.21.0","v2.20.0","v2.19.0","v2.18.0","v2.17.0","v2.16.0","v2.15.0","v2.14.2","v2.14.1","v2.14.0","v2.13.2","v2.13.1","v2.13.0","v2.12.0","v2.11.0","v2.10.1","v2.10.0","v2.9.0","v2.8.1","v2.8.0","v2.7.2","v2.7.1","v2.7.0","v2.6.0","v2.5.0","v2.4.2","v2.4.1","v2.4.0","v2.3.0","v2.2.1","v2.2.0","v2.1.0","v2.0.1","v2.0.0","v1.18.0","v1.17.1","v1.17.0","v1.16.1","v1.16.0","v1.15.1","v1.15.0","v1.14.0","v1.13.3","v1.13.2","v1.13.1","v1.13.0","v1.12.2","v1.12.1","v1.12.0","v1.11.1","v1.11.0","v1.10.1","v1.10.0","v1.9.0","v1.8.1","v1.8.0","v1.7.3","v1.7.2","v1.7.1","v1.6.2","v1.6.1","v1.6.0","v1.5.6","v1.5.5","v1.5.4","v1.5.3","v1.5.2","v1.5.1","v1.5.0","v1.4.1","v1.4.0","v1.3.2","v1.3.1","v1.3.0","v1.2.1","v1.2.0","v1.1.1","v1.1.0","v1.0.1","v1.0.0","v0.9.2","v0.9.1","v0.9.0","v0.8.4","v0.8.3","v0.8.2","v0.8.1","v0.8.0","v0.7.0","v0.6.0","v0.5.0","v0.4.0","v0.3.0","v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45309.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"}]}