The remote Debian host is missing a security-related update.
Several vulnerabilities have been discovered in the ISC DHCP client, relay and server. The Common Vulnerabilities and Exposures project identifies the following issues : - CVE-2017-3144 It was discovered that the DHCP server does not properly clean up closed OMAPI connections, which can lead to exhaustion of the pool of socket descriptors available to the DHCP server, resulting in denial of service. - CVE-2018-5732 Felix Wilhelm of the Google Security Team discovered that the DHCP client is prone to an out-of-bound memory access vulnerability when processing specially constructed DHCP options responses, resulting in potential execution of arbitrary code by a malicious DHCP server. - CVE-2018-5733 Felix Wilhelm of the Google Security Team discovered that the DHCP server does not properly handle reference counting when processing client requests. A malicious client can take advantage of this flaw to cause a denial of service (dhcpd crash) by sending large amounts of traffic.
Upgrade the isc-dhcp packages. For the oldstable distribution (jessie), these problems have been fixed in version 4.3.1-6+deb8u3. For the stable distribution (stretch), these problems have been fixed in version 4.3.5-3+deb9u1.