TZInfo is a Ruby library that provides access to time zone data and allows times to be converted using time zone rules. Versions prior to 0.36.1, as well as those prior to 1.2.10 when used with the Ruby data source tzinfo-data, are vulnerable to relative path traversal. With the Ruby data source, time zones are defined in Ruby files. There is one file per time zone. Time zone files are loaded with require
on demand. In the affected versions, TZInfo::Timezone.get
fails to validate time zone identifiers correctly, allowing a new line character within the identifier. With Ruby version 1.9.3 and later, TZInfo::Timezone.get
can be made to load unintended files with require
, executing them within the Ruby process. Versions 0.3.61 and 1.2.10 include fixes to correctly validate time zone identifiers. Versions 2.0.0 and later are not vulnerable. Version 0.3.61 can still load arbitrary files from the Ruby load path if their name follows the rules for a valid time zone identifier and the file has a prefix of tzinfo/definition
within a directory in the load path. Applications should ensure that untrusted files are not placed in a directory on the load path. As a workaround, the time zone identifier can be validated before passing to TZInfo::Timezone.get
by ensuring it matches the regular expression \A[A-Za-z0-9+\-_]+(?:\/[A-Za-z0-9+\-_]+)*\z
.