CVE-2026-102643
AsyncSSH: SFTPServer Chroot Escape
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 2.24.1, SFTPServer.map_path() uses posixpath.normpath() on a client-supplied path and removes only one leading slash before passing the result to posixpath.join() with the configured chroot. An authenticated SFTP user can supply a path beginning with exactly two slash characters, causing POSIX normalization to preserve the double-leading-slash form and the subsequent join to treat the remaining pathname as absolute. This bypasses the SFTP chroot and permits reads and writes with the operating-system permissions of the account running the server, which may enable code execution depending on writable targets. This issue is fixed in version 2.24.1.
| CWE | CWE-22 CWE-50 |
| Vendor | ronf |
| Product | asyncssh |
| Published | Nov 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H