Sayyiduna Abu Hurayrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "The purification of a vessel, when a dog puts its mouth into it, is that it be washed seven times, the first time with dust; and for a cat, wash it once or twice."
Abu Asim al-Dahhak bin Makhlad is thiqah (trustworthy), except that he erred in inserting the saying of Abu Hurayrah about the cat into the marfu' hadith (attributed to the Prophet) about the dog.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1168