Remote code execution occurs in Apache Solr before 7.1 with Apache Lucene before 7.1 by exploiting XXE in conjunction with use of a Config API add-listener command to reach the RunExecutableListener class. Elasticsearch, although it uses Lucene, is NOT vulnerable to this. Note that the XML external entity expansion vulnerability occurs in the XML Query Parser which is available, by default, for any query request with parameters deftype=xmlparser and can be exploited to upload malicious data to the /upload request handler or as Blind XXE using ftp wrapper in order to read arbitrary local files from the Solr server. Note also that the second vulnerability relates to remote code execution using the RunExecutableListener available on all affected versions of Solr.
Apache Solr's Kerberos plugin can be configured to use delegation tokens, which allows an application to reuse the authentication of an end-user or another application. There are two issues with this functionality (when using SecurityAwareZkACLProvider type of ACL provider e.g. SaslZkACLProvider). Firstly, access to the security configuration can be leaked to users other than the solr super user. Secondly, malicious users can exploit this leaked configuration for privilege escalation to further expose/modify private data and/or disrupt operations in the Solr cluster. The vulnerability is fixed from Apache Solr 6.6.1 onwards.
When using the Index Replication feature, Apache Solr nodes can pull index files from a master/leader node using an HTTP API which accepts a file name. However, Solr before 5.5.4 and 6.x before 6.4.1 did not validate the file name, hence it was possible to craft a special request involving path traversal, leaving any file readable to the Solr server process exposed. Solr servers protected and restricted by firewall rules and/or authentication would not be at risk since only trusted clients and users would gain direct HTTP access.
Apache Solr uses a PKI based mechanism to secure inter-node communication when security is enabled. It is possible to create a specially crafted node name that does not exist as part of the cluster and point it to a malicious node. This can trick the nodes in cluster to believe that the malicious node is a member of the cluster. So, if Solr users have enabled BasicAuth authentication mechanism using the BasicAuthPlugin or if the user has implemented a custom Authentication plugin, which does not implement either "HttpClientInterceptorPlugin" or "HttpClientBuilderPlugin", his/her servers are vulnerable to this attack. Users who only use SSL without basic authentication or those who use Kerberos are not affected.
Cross-site scripting (XSS) vulnerability in webapp/web/js/scripts/plugins.js in the stats page in the Admin UI in Apache Solr before 5.3.1 allows remote attackers to inject arbitrary web script or HTML via the entry parameter to a plugins/cache URI.
Cross-site scripting (XSS) vulnerability in webapp/web/js/scripts/schema-browser.js in the Admin UI in Apache Solr before 5.3 allows remote attackers to inject arbitrary web script or HTML via a crafted schema-browse URL.
Multiple cross-site scripting (XSS) vulnerabilities in the Admin UI in Apache Solr before 5.1 allow remote attackers to inject arbitrary web script or HTML via crafted fields that are mishandled during the rendering of the (1) Analysis page, related to webapp/web/js/scripts/analysis.js or (2) Schema-Browser page, related to webapp/web/js/scripts/schema-browser.js.
Cross-site scripting (XSS) vulnerability in the Admin UI Plugin / Stats page in Apache Solr 4.x before 4.10.3 allows remote attackers to inject arbitrary web script or HTML via the fieldvaluecache object.
The (1) UpdateRequestHandler for XSLT or (2) XPathEntityProcessor in Apache Solr before 4.1 allows remote attackers to have an unspecified impact via XML data containing an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue, different vectors than CVE-2013-6407.