A code injection vulnerability was found in php-gettext. Evaluating the plural form formula in ngettext family of calls can execute arbitrary code if number is passed unsanitized from the untrusted user.

References:

http://seclists.org/fulldisclosure/2016/Aug/76

The Gettext override translations WordPress plugin before 2.0.0 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup)