CVE-2021-21343

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

### Impact The processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. ### Patches If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.16. ### 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-2021-21343](https://x-stream.github.io/CVE-2021-21343.html). ### Credits 钟潦贵 (Liaogui Zhong) 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)

### Impact The processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. ### Patches If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.16. ### 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-2021-21343](https://x-stream.github.io/CVE-2021-21343.html). ### Credits 钟潦贵 (Liaogui Zhong) 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)

XStream es una biblioteca de Java para serializar objetos a XML y viceversa. En XStream anterior a la versión 1.4.16, se presenta una vulnerabilidad en el que el flujo procesado en el momento de la descompensación contiene información de tipo para recrear los objetos escritos anteriormente. XStream crea, por tanto, nuevas instancias basadas en este tipo de información. Un atacante puede manipular el flujo de entrada procesado y reemplazar o inyectar objetos, que resulta en la eliminación de un archivo en el host local. Ningún usuario está afectado, si siguió la recomendación de configurar el framework de seguridad de XStream con una lista blanca limitada a los tipos mínimos requeridos. Si confía en la lista negra predeterminada de XStream del Framework de Seguridad, tendrá que usar al menos la versión 1.4.16