multi_xml gem 0.5.2 for Ruby, as used in Grape before 0.2.6 and possibly other products, does not properly restrict casts of string values, which allows remote attackers to conduct object-injection attacks and execute arbitrary code, or cause a denial of service (memory and CPU consumption) involving nested XML entity references, by leveraging support for (1) YAML type conversion or (2) Symbol type conversion, a similar vulnerability to CVE-2013-0156.

References

• https://nvd.nist.gov/vuln/detail/CVE-2013-0175
• sferik/multi_xml#34
• https://groups.google.com/forum/?fromgroups=#!topic/ruby-grape/fthDkMgIOa0
• https://news.ycombinator.com/item?id=5040457
• https://www.openwall.com/lists/oss-security/2013/01/11/9
• sferik/multi_xml@c94b136