Advisory Weakness Curation

XStream is vulnerable to an Arbitrary Code Execution attack ### Impact The vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. ### Patches XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose. ### Workarounds See workarounds https://x-stream.github.io/security.html#workaround for the different versions covering all CVEs. ### References See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for CVE-2021-39154 https://x-stream.github.io/CVE-2021-39154.html. ### Credits ka1n4t found and reported the issue to XStream and provided the required information to reproduce it. ### For more information If you have any questions or comments about this advisory: * Open an issue in XStream https://github.com/x-stream/xstream/issues * Contact us at XStream Google Group https://groups.google.com/group/xstream-user

Deserialization of Untrusted Data XStream is a simple library to serialize objects to XML and back again. Users who followed the recommendation to setup XStream's security framework with an allow list limited to the minimal required types are not impacted.