From the WordPress 4.9.1 release post: WordPress versions 4.9 and earlier are affected by four security issues which could potentially be exploited as part of a multi-vector attack. As part of the core team’s ongoing commitment to security hardening, the following fixes have been implemented in 4.9.1:
- Use a properly generated hash for the
newbloguserkey instead of a determinate substring.
- Add escaping to the language attributes used on
- Ensure the attributes of enclosures are correctly escaped in RSS and Atom feeds.
List of files revised