Resolving SSL Update Network error:14090086 in WordPress

After a recent upgrade to WordPress 3.5 on a multisite installation, I received an error when using “Update Network” through the GUI. I did some searching via WordPress forums and Google, but did not find anything specific to MU usage.

I did find a non-English site which offered a solution, but it required editing the files within WordPress, something which could be overwritten during an upgrade. Continue reading