Solr versions 1.3.0 to 1.4.1, 3.1.0 to 3.6.2 and 4.0.0 to 4.10.4 are vulnerable to an XML resource consumption attack (a.k.a. Lol Bomb) via it’s update handler.?By leveraging XML DOCTYPE and ENTITY type elements, the attacker can create a pattern that will expand when the server parses the XML causing OOMs.

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.

The UpdateRequestHandler for XML 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.