The updated packages fix security vulnerabilities:
The JPXStream::init function in Poppler 0.78.0 and earlier doesn't check for negative values of stream length, leading to an Integer Overflow, thereby making it possible to allocate a large memory chunk on the heap, with a size controlled by an attacker, as demonstrated by pdftocairo. (CVE-2019-9959)
An issue was discovered in Poppler 0.74.0. There is a heap-based buffer over-read in the function PSOutputDev::checkPageSlice at PSOutputDev.cc. (CVE-2019-10871)