CVE-2026-32147SFTP chroot bypass via path traversal in SSH_FXP_FSETSTAT

Official description

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to modify file attributes outside the configured chroot directory. The SFTP daemon (ssh_sftpd) stores the raw, user-supplied path in file handles instead of the chroot-resolved path. When SSH_FXP_FSETSTAT is issued on such a handle, file attributes (permissions, ownership, timestamps) are modified on the real filesystem path, bypassing the root directory boundary entirely. Any authenticated SFTP user on a server configured with the root option can modify file attributes of files outside the intended chroot boundary. The prerequisite is that a target file must exist on the real filesystem at the same relative path. Note that this vulnerability only allows modification of file attributes; file contents cannot be read or altered through this attack vector. If the SSH daemon runs as root, this enables direct privilege escalation: an attacker can set the setuid bit on any binary, change ownership of sensitive files, or make system configuration world-writable. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routines ssh_sftpd:do_open/4 and ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 before OTP 28.4.3, OTP 27.3.4.11 and OTP 26.2.5.20, corresponding to ssh from 3.0.1 before 5.5.3, 5.2.11.7 and 5.1.4.15.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/erlang/otp/security/advisories/GHSA-28jg-mw9x-hpm5 vendor-advisory, related
• https://cna.erlef.org/cves/CVE-2026-32147.html related
• https://osv.dev/vulnerability/EEF-CVE-2026-32147 related
• https://www.erlang.org/doc/system/versions.html#order-of-versions x_version-scheme
• https://github.com/erlang/otp/commit/28c5d5a6c5f873dc701b597276271763e7d1c004 patch