CVE-2020-26258

XStream is a Java library to serialize objects to XML and back again. In
XStream before version 1.4.15, a Server-Side Forgery Request vulnerability
can be activated when unmarshalling. The vulnerability may allow a remote
attacker to request data from internal resources that are not publicly
available only by manipulating the processed input stream. If you rely on
XStream’s default blacklist of the Security Framework, you will have to use
at least version 1.4.15. The reported vulnerability does not exist if
running Java 15 or higher. No user is affected who followed the
recommendation to setup XStream’s Security Framework with a whitelist!
Anyone relying on XStream’s default blacklist can immediately switch to a
whilelist for the allowed types to avoid the vulnerability. Users of
XStream 1.4.14 or below who still want to use XStream default blacklist can
use a workaround described in more detailed in the referenced advisories.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=977625&gt;