Are any Piriform products vulnerable to CVE-2021-45105, CVE-2021-45046, or CVE-2021-44228? I cannot find any official announcements.
Please read here at the info posted by Avast (who own CCleaner) and you will see that there is nothing to worry about regarding CCleaner products.
https://blog.avast.com/log4j-vulnerability-avast-blog
Also Apache have released several fixes for Java, and Avast being one of the main world players against baddies and vulnerabilities in the antimalware world, will have already updated any of their products toLog4j 2.17.1