An excessively large PDF page size (found in fuzz testing, unlikely in normal PDF files) can result in a divide-by-zero in Xpdf's text extraction code.
This is related to CVE-2022-30524, but the problem here is caused by a very large page size, rather than by a very large character coordinate.
An integer overflow was addressed with improved input validation. This issue is fixed in Security Update 2021-005 Catalina, iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6, watchOS 7.6.2. Processing a maliciously crafted PDF may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
There is an invalid memory access in the function TextString::~TextString() located in Catalog.cc in Xpdf 4.0.2. It can be triggered by (for example) sending a crafted pdf file to the pdftohtml binary, which allows a remote attacker to cause a Denial of Service (Segmentation fault) or possibly have unspecified other impact.
There is an invalid memory access in the function fprintf located in Error.cc in Xpdf 4.0.2. It can be triggered by sending a crafted PDF file to the pdftohtml binary, which allows a remote attacker to cause a Denial of Service (Segmentation fault) or possibly have unspecified other impact.