CVE-2026-48855

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 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to ssh from 3.0.1 before 6.0.1, 5.5.2.1 and 5.2.11.8.

Affected Software

VendorProductVersion RangeStatus
ErlangOTP3.0.1 < *affected
ErlangOTP17.0 < *affected
ErlangOTP08225797f7ef943d0c82a1d9dd6650d94ca2580d < 8f4224a0d2676b0653d2c71a889a956e8c2c62d6affected

Weaknesses

  • CWE-200: CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Workarounds

  • Use OS-level chroot to run the Erlang VM/SFTP server process in an isolated filesystem environment, eliminating reliance on the application-level root option.
  • Ensure that the SFTP server port is not reachable from untrusted machines.
  • Ensure that no sensitive information (usernames, project names, mount topology) is inferrable from the absolute path of the configured root directory.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References