By all means, please don't use cjson -- it's buggy as hell -- but if you must...

I was bit by the same bug as described here: http://blog.extracheese.org/2007/07/when-json-isnt-json.html
So I produced a fix, here is the patch: http://www.vazor.com/media/python-cjson-1.0.5.diff
And the full package now called 1.0.6: http://www.vazor.com/media/python-cjson-1.0.6.tar.gz

And the changelog:

 Changes in version 1.0.6
 ------------------------

 * Escape the solidus (forward slash '/') for encoding and unescape it for
   decoding.
 * Correct read/write solidus unit tests
 * Merge additional unittests from json-py for comments.  All these tests
   currently fail since comments aren't part of the standard json grammar.