The ruby-openid gem before 2.2.2 for Ruby allows remote OpenID providers to cause a denial of service (CPU consumption) via (1) a large XRDS document or (2) an XML Entity Expansion (XEE) attack.
lists.fedoraproject.org/pipermail/package-announce/2013-November/120204.html
lists.fedoraproject.org/pipermail/package-announce/2013-November/120361.html
www.openwall.com/lists/oss-security/2013/03/03/8
bugzilla.redhat.com/show_bug.cgi?id=918134
github.com/advisories/GHSA-6c8p-qphv-668v
github.com/openid/ruby-openid
github.com/openid/ruby-openid/blob/master/CHANGELOG.md
github.com/openid/ruby-openid/commit/a3693cef06049563f5b4e4824f4d3211288508ed
github.com/openid/ruby-openid/pull/43
github.com/rubysec/ruby-advisory-db/blob/master/gems/ruby-openid/CVE-2013-1812.yml
nvd.nist.gov/vuln/detail/CVE-2013-1812