Provide references for CVE-2021-30940.
Where can I find more information about CVE-2021-30940?
References are available at: https://support.apple.com/en-us/HT212976, https://support.apple.com/en-us/HT212978, https://support.apple.com/en-us/HT212979, https://support.apple.com/en-us/HT212981.