The linked blog post is very much worth a read too ( https://medium.com/realmodelabs/kindledrip-from-your-kindles-email-address-to-using-your-credit-card-bb93db

The linked blog post is very much worth a read too ( https://medium.com/realmodelabs/kindledrip-from-your-kindles-email-address-to-using-your-credit-card-bb93dbfb2a08 https://medium.com/realmodelabs/kindledrip-from-your-kindles... ) and includes such gems as - "The reference code prevents this issue with an assert that checks num_channels is less then MAX_CHANNELS. But maybe the Kindle developers missed it? I popped libjpegXR.so in Ghidra to look at how they chose to implement it."