Critical SSHFS Symlink Escape Lets Rogue SFTP Servers Access Local Files

A critical flaw tracked as CVE-2026-47187 affects SSHFS versions earlier than 3.7.6, allowing a malicious or rogue SFTP server to trigger local file read or write on a client system through crafted symlinks. The issue stems from SSHFS passing absolute symlink targets or relative targets containing .. traversal components through FUSE, after which the local kernel VFS can resolve those paths outside the mounted filesystem. If a user or client-side tool such as cp, rsync, backup software, or an editor follows the link, local readable files can be exposed or attacker-controlled data can be written into writable local files, including startup or scheduled-task locations.

The fix was merged into libfuse/sshfs as a new contain_symlinks protection that is enabled by default and rejects absolute symlink targets and any target containing .., returning EPERM. Maintainers described the approach as intentionally strict and lexical because an adversarial filesystem can manipulate intermediate path components, making depth-based checks unreliable. The update also adds a no_contain_symlinks opt-out for trusted legacy environments, updates documentation, and includes tests covering blocked traversal attempts, safe symlinks, option precedence, and interactions with transform_symlinks.