Questioner:

Is there a adīth that mentions the virtues of reciting Sūrah al-Kahf [on Fridays]?

Shaykh ʿAbd al-ʿAzīz bin ʿAbdullāh bin Bāz:

There is a narration [attributed to the companions but not to the Prophet] which mentions that some of the Companions use to read it on Friday. However the adīth which is attributed to the Prophet is weak. It has been reported on the authority of some Companions and this in reality takes the ruling of Raf’ [attributed to the Prophet] because the Companions memorised it, which indicates he heard something from the Messenger of Allah.