SFTP READLINK Leaks Absolute Backend Filesystem Path When Root Is Configured

Summary

Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Erlang OTP ssh (ssh_sftpd module) allows File Discovery. The SSH_FXP_READLINK handler in ssh_sftpd sends the raw result of file:read_link/2 to the client without calling chroot_filename/2 to strip the backend root prefix. An authenticated SFTP client can create a symlink inside the chroot pointing to /; ssh_sftpd resolves the target to the absolute backend root and stores it on disk. Reading the symlink back via SSH_FXP_READLINK returns that absolute path, for example /data/sftp, instead of the chrooted value /. The information disclosed is the absolute filesystem path of the SFTP root directory and of any symlink targets within it. No file contents, credentials, or access to paths outside the root directory are obtainable through this issue alone. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl. This issue affects OTP from OTP 17.0 before OTP 27.3.4.13, OTP 28.5.0.2, and OTP 29.0.2, corresponding to ssh from 3.0.1 before 5.2.11.8, 5.5.2.1, and 6.0.1. Whether OTP before OTP 17.0, corresponding to ssh before 3.0.1, is affected is unknown.

Timeline

1. Jun 10, 2026, 2:35 PM UTCCVE published
2. Jun 10, 2026, 4:22 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Sep 24, 2026, 8:35 PM UTCRecord last updated

Affected versions

• otp

  From 17.0 · fixed in *

• ssh

  From 3.0.1 · fixed in *

• erlang/otp

  From 08225797f7ef943d0c82a1d9dd6650d94ca2580d · fixed in 8f4224a0d2676b0653d2c71a889a956e8c2c62d6

References 6