Debian Security Advisory

DLA-2769-1 libxstream-java -- LTS security update

Date Reported:

30 Sep 2021

Affected Packages:

Vulnerable:

Yes

Security database references:

In Mitre's CVE dictionary: CVE-2021-39139, CVE-2021-39140, CVE-2021-39141, CVE-2021-39144, CVE-2021-39145, CVE-2021-39146, CVE-2021-39147, CVE-2021-39148, CVE-2021-39149, CVE-2021-39150, CVE-2021-39151, CVE-2021-39152, CVE-2021-39153, CVE-2021-39154.

More information:

Multiple security vulnerabilities have been discovered in XStream, a Java library to serialize objects to XML and back again.

These vulnerabilities may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream.

XStream itself sets up a whitelist by default now, i.e. it blocks all classes except those types it has explicit converters for. It used to have a blacklist by default, i.e. it tried to block all currently known critical classes of the Java runtime. Main reason for the blacklist were compatibility, it allowed to use newer versions of XStream as drop-in replacement. However, this approach has failed. A growing list of security reports has proven, that a blacklist is inherently unsafe, apart from the fact that types of 3rd libraries were not even considered. A blacklist scenario should be avoided in general, because it provides a false sense of security.

For Debian 9 stretch, these problems have been fixed in version 1.4.11.1-1+deb9u4.

We recommend that you upgrade your libxstream-java packages.

For the detailed security status of libxstream-java please refer to its security tracker page at: https://security-tracker.debian.org/tracker/libxstream-java

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS