The REXML parser in Ruby 1.9.x before 1.9.3-p550, 2.0.x before 2.0.0-p594, and 2.1.x before 2.1.4 allows remote attackers to cause a denial of service (memory consumption) via a crafted XML document, aka an XML Entity Expansion (XEE) attack.
Exploitability
AV:NAC:LAu:NImpact
C:NI:NA:P5/AV:N/AC:L/Au:N/C:N/I:N/A:P