The remote Debian host is missing a security-related update.
Multiple vulnerabilities have been discovered in the libtiff library and the included tools, which may result in denial of service or the execution of arbitrary code.
Upgrade the tiff packages. For the oldstable distribution (jessie), these problems have been fixed in version 4.0.3-12.3+deb8u5. For the stable distribution (stretch), these problems have been fixed in version 4.0.8-2+deb9u2.