Is the Bug with qlockfile qauthenticator on windows platform plugin fixed in any release

Can somebody tell me if this problem is fixed in an official Qt-release?
https://www.qt.io/blog/security-advisory-qlockfile-qauthenticator-windows-platform-plugin

I dont want to pay much effort in patching my Qt5.15.8 from source build with these patches.
I cant find any informations in the Qt forum or in the www.
In the 5.15.9 release I cant find anything in the release note.