The sanitize helper in lib/action_controller/vendor/html-scanner/html/sanitizer.rb in the Action Pack component in Ruby on Rails before 2.3.18, 3.0.x and 3.1.x before 3.1.12, and 3.2.x before 3.2.13 does not properly handle encoded : (colon) characters in URLs, which makes it easier for remote attackers to conduct cross-site scripting (XSS) attacks via a crafted scheme name, as demonstrated by including a : sequence.
ActiveRecord in Ruby on Rails before 2.3.17 and 3.x before 3.1.0 allows remote attackers to cause a denial of service or execute arbitrary code via crafted serialized attributes that cause the +serialize+ helper to deserialize arbitrary YAML.
The Authlogic gem for Ruby on Rails, when used with certain versions before 3.2.10, makes potentially unsafe find_by_id method calls, which might allow remote attackers to conduct CVE-2012-6496 SQL injection attacks via a crafted parameter in environments that have a known secret_token value, as demonstrated by a value contained in secret_token.rb in an open-source product.