Provide references for CVE-2021-33040.
Where can I find more information about CVE-2021-33040?
References are available at: https://github.com/futurepress/epub.js/blob/5c7f21d648d9d20d44c6c365d164b16871847023/src/managers/views/iframe.js#L373, https://github.com/futurepress/epub.js/compare/v0.3.88...v0.3.89, https://github.com/futurepress/epub.js/commit/ab4dd46408cce0324e1c67de4a3ba96b59e5012e.