A memory denial-of-service vulnerability exists in Pillow's TIFF and EXIF IFD parsing due to overlapping tag data. Crafted image files can cause Pillow to consume thousands of times their size in memory during parsing, leading to process crashes or stalls. This affects TIFF, JPEG, PNG, WebP, and MPO images. The flaw has existed since Pillow 1.0 and involves unbounded memory allocation when reading tag data offsets that overlap or cover the entire file.