Sensitive file disclosure via sender symlink race

Race condition in rsync 3.3.0 and earlier allows local users to read files accessible to a privileged sender via a symlink swap. The sender classifies a source path as a regular file, then later opens that pathname for checksumming or transfer without safely excluding a substituted symbolic link. Exploitation requires write access to the source path and precise timing; the disclosed data is limited to files readable by the rsync process.