In Artifex MuPDF 1.13.0, the fz_append_byte function in fitz/buffer.c allows remote attackers to cause a denial of service (segmentation fault) via a crafted pdf file. This is caused by a pdf/pdf-device.c pdf_dev_alpha array-index underflow.

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.

In MuPDF 1.13.0, there is an infinite loop in the fz_skip_space function of the pdf/pdf-xref.c file. A remote adversary could leverage this vulnerability to cause a denial of service via a crafted pdf file.