An issue was discovered in OpenSatKit 2.2.1. The EventErrStr buffer has a fixed size of 256 bytes. The code uses sprintf to format two filenames (Source1Filename and the string returned by FileUtil_FileStateStr) into this buffer without any length checking and without using bounded format specifiers such as %.*s. If the filename length approaches OS_MAX_PATH_LEN (commonly 64-256 bytes), the combined formatted string together with constant text can exceed 256 bytes, resulting in a stack buffer overflow. Such unsafe sprintf calls are scattered across multiple functions in file.c, including FILE_ConcatenateCmd() and ConcatenateFiles(), all of which fail to validate the output length.