In libxml2 before 2.13.8 and 2.14.x before 2.14.2, out-of-bounds memory access can occur in the Python API (Python bindings) because of an incorrect return value. This occurs in xmlPythonFileRead and xmlPythonFileReadRaw because of a difference between bytes and characters.
A function or operation returns an incorrect return value or status code that does not indicate an error, but causes the product to modify its behavior based on the incorrect result.