I dunno if it's the most current, but 1.6.0_24 is supported: http://blogs.coldfusion.com/post.cfm/jdk-1-6-0-24-is-now-officially-supported
The baseline systemre requirements for CF8 are: http://www.adobe.com/products/coldfusion/coldfusion8/systemreqs/ (which say Sun JDK 1.4.2_14, 1.5_13, and 1.6_04)
According to reference - Upgrade Java for ColdFusion:
You can apply any Java minor version.
CF8.0.0 used 1.6.0_00 and CF8.0.1 used 1.6.0_04. I expect you could install current 1.6.0_37 tho I have not used CF8.0.1 beyond 1.6.0_31 (on Windows 32 bit).
Prompts the question what about Java 7 since Java 6 is EOL next month (I think Oracle may have pushed Java 6 EOL back to February 2013)? CF10 and CF9 are not supported Java 7 yet however I gather will be supported before EOL. Not aware of CF8 Java 7 support.