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.
mail-archives.us.apache.org/mod_mbox/www-announce/201710.mbox/%3CCAOOKt51UO_6Vy%3Dj8W%3Dx1pMbLW9VJfZyFWz7pAnXJC_OAdSZubA%40mail.gmail.com%3E
openwall.com/lists/oss-security/2017/10/13/1
www.securityfocus.com/bid/101261
access.redhat.com/errata/RHSA-2017:3123
access.redhat.com/errata/RHSA-2017:3124
access.redhat.com/errata/RHSA-2017:3244
access.redhat.com/errata/RHSA-2017:3451
access.redhat.com/errata/RHSA-2017:3452
access.redhat.com/errata/RHSA-2018:0002
access.redhat.com/errata/RHSA-2018:0003
access.redhat.com/errata/RHSA-2018:0004
access.redhat.com/errata/RHSA-2018:0005
lists.apache.org/thread.html/r140128dc6bb4f4e0b6a39e962c7ca25a8cbc8e48ed766176c931fccc%40%3Cusers.solr.apache.org%3E
lists.apache.org/thread.html/r26c996b068ef6c5e89aa59acb769025cfd343a08e63fbe9e7f3f720f%40%3Coak-issues.jackrabbit.apache.org%3E
lists.apache.org/thread.html/r3da74965aba2b5f5744b7289ad447306eeb2940c872801819faa9314%40%3Cusers.solr.apache.org%3E
lists.apache.org/thread.html/r95df34bb158375948da82b4dfe9a1b5d528572d586584162f8f5aeef%40%3Cusers.solr.apache.org%3E
lists.debian.org/debian-lts-announce/2018/01/msg00028.html
s.apache.org/FJDl
twitter.com/ApacheSolr/status/918731485611401216
twitter.com/joshbressers/status/919258716297420802
twitter.com/searchtools_avi/status/918904813613543424
usn.ubuntu.com/4259-1/
www.debian.org/security/2018/dsa-4124
www.exploit-db.com/exploits/43009/