This release only contains the security fix; no other changes have been made compared to the Joomla! 4.2.7 release.
After the release, we strongly advise you to renew the passwords for all credentials that are stored in the global site configuration, namely:
The issue has been reported in a responsible disclosure process, there have been no signs of exploitation on public sites.
 - Core - Improper access check in webservice endpoints
New installation instructions and technical requirements