[Citation needed]

>NSA has implemented backdoors in software through bug fixes that appear to be just benign typo or spelling fixes but actually allow an exploit in combination with some other exploit etc.

I dunno why you needed a citation for this it is literally the NSA's job to do this, if you weren't just trolling me you must be living under a rock.

https://www.wired.com/2014/04/nsa-exploited-heartbleed-two-y...