Note that the Angular team is working with Mozilla and the researcher on this (see https://github.com/mozilla/addons-linter/issues/1000#issueco...) and that NDAs are a real, if insane, thing still to this day, and there is literally no way to legally compel any party to admit to being under NDA except in a court of law.
Should the researcher have told the Angular team? Yes. Should they have told the entire world? Probably no. Should Mozilla tell the world? Probably even less no. As long as the parties are talking (which they are), this is an unfinished security review on lock-down to prevent exploitation in the interrim.
Should the researcher have told the Angular team? Yes. Should they have told the entire world? Probably no. Should Mozilla tell the world? Probably even less no. As long as the parties are talking (which they are), this is an unfinished security review on lock-down to prevent exploitation in the interrim.