Does cat fur invalidate our prayers?
Regarding cats, the Prophet Muhammad PBUH is quoted as saying:
إنها ليست بنجس، إنها من الطوافين عليكم
It is not impure. It is allowed to be a tawwāf (that which freely moves around) upon you (in your homes).1
The purity extends to its hair according to the Yemeni scholar al-Ṣanʿānī (1687 – 1768 CE).2, meaning that there is no issue with praying with cat hairs on you while praying.