I'm missing a link to a page describing how to handle patches related to security issues.
Given that these shouldn't be uploaded to Gerrit, it's worth mentioning here, especially because I cannot find it anywhere right now.
I eventually found Reporting security bugs#Contributing Patches, but that isn't linked nor does it mention (or link) how to submit those patches!
Even more searching leads to https://wikitech.wikimedia.org/wiki/How_to_deploy_code#Security_patches.
This is worthless, and cost me five minutes I'd rather not waste when dealing with security issues.