php: Buffer over-read in exif_process_IFD_TAG() leading to information disclosure

When processing certain files, PHP EXIF extension in versions 7.1.x below 7.1.29, 7.2.x below 7.2.18 and 7.3.x below 7.3.5 can be caused to read past allocated buffer in exifprocessIFDTAG function. This may lead to information disclosure or crash...