CVE-2017-7660: Security Vulnerability in secure inter-node communication in Apache Solr Severity: Important Vendor: The Apache Software Foundation Versions Affected: Solr 5.3 to 5.5.4 Solr 6.0 to 6.5.1 Description: 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. Mitigation: 6.x users should upgrade to 6.6 5.x users should obtain the latest source from git and apply this patch: http://git-wip-us.apache.org/repos/asf/lucene-solr/commit/2f5ecbcf Credit: This issue was discovered by Noble Paul of Lucidworks Inc. References: https://issues.apache.org/jira/browse/SOLR-10624 https://wiki.apache.org/solr/SolrSecurity -- The Lucene PMC