A logic error in the split utility of uutils coreutils causes the corruption of output filenames when provided with non-UTF-8 prefix or suffix inputs. The implementation utilizes to_string_lossy() when constructing chunk filenames, which automatically rewrites invalid byte sequences into the UTF-8 replacement character (U+FFFD). This behavior diverges from GNU split, which preserves raw pathname bytes intact.

In environments utilizing non-UTF-8 encodings, this vulnerability leads to the creation of files with incorrect names, potentially causing filename collisions, broken automation, or the misdirection of output data.