Tatoeba contains this sentence: 你什么名字?. Usually the phrase "What is your name?" is translated as "你叫什么名字？". Is "你什么名字?" correct?
What is idiomatic in English does not mean its literal counterpart is idiomatic in Chinese. For instance, we don't say
你多老for 'How old are you?' – that would be surely a mistranslation.
Grammaticality and idiomaticity are separate things. I must disagree with r13's claim that
你什麼名字is ungrammatical because it lacks a verb. It is at most unidiomatic (except in very limited circumstances, e.g. police interrogation as suggested by Wayne Cheah). Many Chinese sentences are of the topic-comment construction which permits the absence of a verb:
這個人個子很高。 lit. Regarding this person (topic), his stature is tall (comment).
Also, just because you can insert a verb into the verbless sentence does not prove the verbless sentence is ungrammatical.
Honorifics are idiomatic in Chinese when it comes to salutatory or courteous exchanges. It is especially not a good idea to translate expressions into Chinese literally in these instances. For example, we use
您(honorific 2nd person singular pronoun) and
貴姓('surname', honorific) when we ask for someone's surname (depending on the context, it can be rude if we ask for someone's full name):
Of course, when you are meeting someone for the first time, when that person shares a similar social status to you, and when you want to be especially courteous, you may ask for their full name like so:
請問該怎麼稱呼您？ lit. How may I address you?
These examples are not exhaustive. But they are much more idiomatic expressions than
你什么名字？ is grammatically correct, however does feel somewhat rude, as if less words were included because you cared too little to include them.
I can understand you feel it might be grammatically incorrect, but if we look at phrases like
你什么时候去ta的家?, it's basically using the same construction (no word between the 你 and the question word
什么时候). The only reason this one feels more grammatically correct than the other is because we have gotten used to hearing this construction frequently.