It was found that XStream is vulnerable to Remote Code Execution. The vulnerability may allow a remote attacker to run arbitrary shell commands only by manipulating the processed input stream. Users who rely on blocklists are affected (the default in Debian). We strongly recommend to use the whitelist approach of XStream’s Security Framework because there are likely more class combinations the blacklist approach may not address.
For Debian 8 jessie, these problems have been fixed in version 1.4.7-2+deb8u3.
We recommend that you upgrade your libxstream-java packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/