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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| asyncssh ronf |
< 2.24.1 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 8.8 high |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/ronf/asyncssh/security/advisories/GHSA-w29m-45fc-22v9CNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/ronf/asyncssh/commit/d4fc430d37b234cb35f1ba2cca834b2dbe1302cfCNA: GitHub_M · x_refsource_MISC
- https://github.com/ronf/asyncssh/releases/tag/v2.24.1CNA: GitHub_M · x_refsource_MISC
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