I tested this against 6.3.3 and was able to run the arbitrary commands against the target host.
After installing the patch, further attempts were met with this error:
"No client SSL certificate supplied".
*** Bug 1630489 has been marked as a duplicate of this bug. ***
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
Created redmine issue https://projects.theforeman.org/issues/25001 from this bug