The Donation Thermometer WordPress plugin before 2.3.0 does not escape a colour value taken from a shortcode attribute before using it in an attribute of the generated legend markup, allowing users with the Contributor role and above to inject arbitrary event handlers that execute when the page is viewed.

The Donation Thermometer WordPress plugin before 2.3.0 does not escape a colour value taken from a shortcode attribute before using it in an attribute of the generated legend markup, allowing users with the Contributor role and above to inject arbitrary event handlers that execute when the page is viewed.