The remote Debian host is missing a security-related update.
Two issues were discovered in the Tomcat servlet and JSP engine. - CVE-2017-7674 Rick Riemer discovered that the Cross-Origin Resource Sharing filter did not add a Vary header indicating possible different responses, which could lead to cache poisoning. - CVE-2017-7675 (stretch only) Markus Dorschmidt found that the HTTP/2 implementation bypassed some security checks, thus allowing an attacker to conduct directory traversal attacks by using specially crafted URLs.
Upgrade the tomcat8 packages. For the oldstable distribution (jessie), these problems have been fixed in version 8.0.14-1+deb8u11. For the stable distribution (stretch), these problems have been fixed in version 8.5.14-1+deb9u2.