KB4512506 and KB4512486 not available with Symantec Endpoint Protection or Norton Antivirus (4306382)

Microsoft updates KB4512506 / KB4512486 are not available for Windows 7 SP1 / Windows 2008 R2 SP1 running Symantec Endpoint Protection or Norton Antivirus.

Per Microsoft:

Microsoft has temporarily placed a safeguard hold on devices with an affected version of Symantec Antivirus or Norton Antivirus installed to prevent them from receiving this type of Windows update until a solution is available. We recommend that you do not manually install affected updates until a solution is available.

Guidance for Symantec customers can be found in the Symantec support article.