Error during converting jpg to pdf

This problems comes from a security update: https://launchpad.net/ubuntu/+source/imagemagick/8:6.8.9.9-7ubuntu5.13

Someone reported it as a bug: https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1796563

As a temporary fix, I edited /etc/ImageMagick-6/policy.xml and changed the PDF rights from none to read|write there. Not sure about the implications, but at least it allows me to get things done.

Fixed this on my Ubuntu 16.04.6 LTS by following accepted answer.

Created simple sed one-liner to get this fixed faster:

sudo sed -i 's#<policy domain="coder" rights="none" pattern="PDF" />#<policy domain="coder" rights="read|write" pattern="PDF" />#' /etc/ImageMagick-6/policy.xml

and in programmatic way.

If you're worried about the implications, https://bugs.launchpad.net/ubuntu/+source/imagemagick/+bug/1796563 mentions that

While the release notes are not exactly clear, Ghostscript v9.25 seems to make reference to fixing some vulnerabilities of this sort: https://www.ghostscript.com/doc/9.25/News.htm