The remote Debian host is missing a security-related update.
Multiple vulnerabilities were discovered in the poppler PDF rendering library, which could result in denial of service or the execution of arbitrary code if a malformed PDF file is processed.
Upgrade the poppler packages. For the oldstable distribution (jessie), these problems have been fixed in version 0.26.5-2+deb8u2. For the stable distribution (stretch), these problems have been fixed in version 0.48.0-2+deb9u1.