In Artifex MuPDF 1.13.0, the pdf_get_xref_entry function in pdf/pdf-xref.c allows remote attackers to cause a denial of service (segmentation fault in fz_write_data in fitz/output.c) via a crafted pdf file.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.