What is the ruling on the commission received by a recruitment agency for matching job seekers with companies, and is it permissible to accept salaries from it?

There is no objection to the commission taken by the company for providing employees. This falls under the category of ijara (leasing/hiring) or ja'ala (commission/reward) for mediation, provided that the work is based on sincerity, truthfulness, and trustworthiness. The scholars of the Permanent Committee have issued a fatwa permitting the taking of commission in such cases. Sheikh Ibn Baz concurred with them, provided there is no treachery or deception, and that the work is conducted with honesty and truthfulness.