The remote Debian host is missing a security-related update.
Several vulnerabilities were discovered in libsmpack, a library used to handle Microsoft compression formats. A remote attacker could craft malicious CAB, CHM or KWAJ files and use these flaws to cause a denial of service via application crash, or potentially execute arbitrary code.
Upgrade the libmspack packages. For the stable distribution (stretch), these problems have been fixed in version 0.5-1+deb9u2.