Heap buffer overflow vulnerability in libjxl 0.12.0 via crafted PBM images to the jxl::extras::DecodeImagePNM function in file lib/extras/dec/pnm.cc.

A heap buffer overflow vulnerability has been discovered in libjxl version 0.12.0. The vulnerability occurs in the jxl::extras::DecodeImagePNM function located in lib/extras/dec/pnm.cc when processing specially crafted PBM images. This memory corruption issue could potentially allow attackers to execute arbitrary code or cause denial of service by providing malicious PBM image files to applications using the affected libjxl library. The vulnerability has been reported through GitHub issues and pull requests, with proof-of-concept exploits available.