More information about this security flaw is available in the following bug: https://bugzilla.redhat.com/show_bug.cgi?id=2326998 Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Since only versions of PostCSS prior to 8.4.31 are affected, this is not an issue for the Fedora 40 build of python-nbdime, which has PostCSS version 8.4.45.