Plugins - Update Failed: Download failed. cURL error 77

I get this error whenever I try to run updates on plugins:
Update Failed: Download failed. cURL error 77: Problem with the SSL CA cert (path? access rights?)

The only way around it seems to be to deactivate all plugins, run the updates, then re-activate.

I have tried deactivating individual plugins and attempting the updates in an effort to pinpoint the culpruit, but to no avail.