libjxl b02d6b9, as used in libvips 8.11 through 8.11.2 and other products, has an out-of-bounds write in jxl::ModularFrameDecoder::DecodeGroup (called from jxl::FrameDecoder::ProcessACGroup and jxl::ThreadPool::RunCallState<jxl::FrameDecoder::ProcessSections).