Is it true that swearing can break your Wudu (ablution) and therefore needs to be performed again?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Invoking a curse or swearing does not break ones ablution as there is no evidence about this.

Nonetheless, these are not the qualities of a Muslim; the Prophet said: "A believer is neither a slanderer nor a curser, nor is he obscene or vulgar." [Ahmed and Ibn Hibbaan]

Therefore, a Muslim should avoid cursing and swearing to protect his religion and control his tongue.

To know what invalidates ablution, you can refer to Fatwa No: 84093.

Allaah knows best.