The remote Debian host is missing a security-related update.
Several vulnerabilities have been discovered in Squid3, a fully featured web proxy cache. The Common Vulnerabilities and Exposures project identifies the following issues : - CVE-2018-1000024 Louis Dion-Marcil discovered that Squid does not properly handle processing of certain ESI responses. A remote server delivering certain ESI response syntax can take advantage of this flaw to cause a denial of service for all clients accessing the Squid service. This problem is limited to the Squid custom ESI parser. - CVE-2018-1000027 Louis Dion-Marcil discovered that Squid is prone to a denial of service vulnerability when processing ESI responses or downloading intermediate CA certificates. A remote attacker can take advantage of this flaw to cause a denial of service for all clients accessing the Squid service.
Upgrade the squid3 packages. For the oldstable distribution (jessie), these problems have been fixed in version 3.4.8-6+deb8u5. For the stable distribution (stretch), these problems have been fixed in version 3.5.23-5+deb9u1.