Multiple security issues have been found in the JBIG2 decoder library, which may lead to lead to denial of service or the execution of arbitrary code if a malformed image file (usually embedded in a PDF document) is opened (CVE-2016-9601). Artifex jbig2dec has a heap-based buffer over-read leading to denial of service (application crash) because of an integer overflow in the jbig2_decode_symbol_dict function in jbig2_symbol_dict.c in libjbig2dec.a during operation on a crafted .jb2 file (CVE-2017-7885). Artifex jbig2dec allows out-of-bounds writes because of an integer overflow in the jbig2_build_huffman_table function in jbig2_huffman.c during operations on a crafted JBIG2 file, leading to a denial of service (application crash) or possibly execution of arbitrary code (CVE-2017-7975). Artifex jbig2dec allows out-of-bounds writes and reads because of an integer overflow in the jbig2_image_compose function in jbig2_image.c during operations on a crafted .jb2 file, leading to a denial of service (application crash) (CVE-2017-7976).