If you installed the free version of CCleaner after Aug. 15, a couple of nasty programs came along for the ride. Talos Intelligence, a division of Cisco, just published a damning account of malware that it found hiding in the installer for CCleaner 5.33, the version that was released on Aug. 15 and which, according to Talos, was still the primary download on the official CCleaner page on Sept. 11.
After notifying Piriform, CCleaner was, ahem, cleaned up and version 5.34 appeared on Sept. 12.
I just checked, and the current version available from Piriform is version 5.34. (Piriform was bought by antivirus giant Avast in July.)