libjbig2dec.a in Artifex jbig2dec 0.13, as used in MuPDF and Ghostscript, has a NULL pointer dereference in the jbig2_huffman_get function in jbig2_huffman.c. For example, the jbig2dec utility will crash (segmentation fault) when parsing an invalid file.
https://lists.debian.org/debian-lts-announce/2021/10/msg00023.html
https://git.ghostscript.com/?p=ghostpdl.git%3Ba=commit%3Bh=3ebffb1d96ba0cacec23016eccb4047dab365853