The remote Debian host is missing a security-related update.
Several vulnerabilities were discovered in CUPS, the Common UNIX Printing System. These issues have been identified with the following CVE ids : - CVE-2017-15400 Rory McNamara discovered that an attacker is able to execute arbitrary commands (with the privilege of the CUPS daemon) by setting a malicious IPP server with a crafted PPD file. - CVE-2018-4180 Dan Bastone of Gotham Digital Science discovered that a local attacker with access to cupsctl could escalate privileges by setting an environment variable. - CVE-2018-4181 Eric Rafaloff and John Dunlap of Gotham Digital Science discovered that a local attacker can perform limited reads of arbitrary files as root by manipulating cupsd.conf. - CVE-2018-6553 Dan Bastone of Gotham Digital Science discovered that an attacker can bypass the AppArmor cupsd sandbox by invoking the dnssd backend using an alternate name that has been hard linked to dnssd.
Upgrade the cups packages. For the stable distribution (stretch), these problems have been fixed in version 2.2.1-8+deb9u2.