{"id":"DEBIAN-CVE-2026-45309","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.","modified":"2026-09-01T16:06:45.183781483Z","published":"2026-07-17T19:17:14.333Z","upstream":["CVE-2026-45309"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-45309"}],"affected":[{"package":{"name":"python-asyncssh","ecosystem":"Debian:12","purl":"pkg:deb/debian/python-asyncssh?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.1-2","2.10.1-2+deb12u1","2.10.1-2+deb12u2","2.15.0-1","2.16.0-1","2.17.0-1","2.17.0-2","2.18.0-1","2.19.0-1","2.20.0-1","2.21.0-1","2.21.1-1","2.22.0-1","2.22.0-2","2.23.0-1","2.24.0-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-45309.json"}},{"package":{"name":"python-asyncssh","ecosystem":"Debian:13","purl":"pkg:deb/debian/python-asyncssh?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.20.0-1","2.21.0-1","2.21.1-1","2.22.0-1","2.22.0-2","2.23.0-1","2.24.0-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-45309.json"}},{"package":{"name":"python-asyncssh","ecosystem":"Debian:14","purl":"pkg:deb/debian/python-asyncssh?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.23.0-1"}]}],"versions":["2.20.0-1","2.21.0-1","2.21.1-1","2.22.0-1","2.22.0-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-45309.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}