¿Qué me le pasó?

[poli]

This was used to mean, what happened to you?
I have never seen this usage before. Is it commonly used?

[wrholt]

I think native speakers will have to chime in on this, but:

The range of possible uses for object pronouns in Spanish (me, nos, te, os, lo, la, le, los, las, les, se) is a LOT wider than the the range of possible uses for object pronouns in English (me, us, you, him, her, it, them).

Assuming that the sentence "¿Qué me le pasó?" is a valid sentence, I think it has 2 indirect object pronouns. Le is the indirect object pronoun that we expect, filling the role of the dativo de interés. Me is an additional indirect object pronoun filling a different role, perhaps one identified in some sources as dativo ético: I think that the intended meaning is that "I" am in some manner affected by whatever it was that happened to you.

[AngelicaDeAlquezar]

I agree with Wrholt.
This use of the "me" is a colloquial way to express I'm concerned about you, I care about you and the things that happen to you are as if they happen to me. :)
I haven't heard it used like this in Mexico, but I've heard it in Colombian telenovelas.

Yet, you may hear some Mexican mothers talk about the things their children do as if they were doing those things to aggravate them:
- La niña no me come. -> My daughter won't eat as much as I'd like her to, and I live it like a personal offense. Maybe the child is sick, but the mother expresses her worries as if the child had an intention to hurt her. :D
- Juanito me reprobó tres materias. -> My son failed three subjects in school, and I'm expressing it as if he did it to bother me.
- Los escuincles se fueron a una fiesta y me regresaron borrachos. -> My kids went to a party and they got drunk "just because they know that makes me mad". ;)