Improper Restriction of XML External Entity Reference
The DocumentAnalysisRequestHandler in Apache Solr before 4.3.1 does not properly use the EmptyEntityResolver, which 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. NOTE: this vulnerability exists because of an incomplete fix for CVE-2013-6407.
CWE-611 - Improper Restriction of XML External Entity Reference
Listed 4th in the 'OWASP Top Ten', XML External Entities (XXE) vulnerability allows attackers to provide an XML input that contains an external entity. When the XML is parsed, it can cause data extraction and manipulation, execution of commands, denial-of-service attacks, and server-side request forgery.