Critical Regression: smbfs 7.0 introduces a crtitical bug regarding symlinks

Apple feedback FB25355124

The SMB client no longer accepts reads to symlinks that are an absolute path to a network volume or a symlink that contains a (..) in the relative path.

Reproduction steps on an SMB mount with this file structure:

  • dir
    • a.txt
  1. Run this command from inside of "dir":

    ln -s my-link ../dir/a.txt

  2. Attempt to read that symlink:

    cat ./my-link

    Which results in this error:
    cat: link: Invalid argument

    which is translating to an EINVAL getting returned from the SMB client.

  3. Same behavior was observed when making a symlink with an absolute path:

    ln -s my-link /Volumes/Example/dir/a.txt

The server is responding successfully to the IOCTL command but the client is still rejecting the request with that error.

This behavior was not observed in macOS 26.6.2 (smbfs 6.0.1) as well as previous versions of macOS.