Versions of the package exifreader before 4.39.0 are vulnerable to Improper Handling of Highly Compressed Data (Data Amplification) due to decompressing PNG zTXt metadata without enforcing a built-in maximum decompressed output size. When asynchronous parsing is enabled, a crafted PNG file containing a highly compressed zTXt chunk can cause ExifReader to materialize a disproportionately large Comment value in memory.