TYPO3 Core

Since the version 10.4.18 i can't output an iframe anymore.

All iFrames are escaped in the output since some of the last version.

<p>&lt;iframe allowfullscreen frameborder="0" height="360" src="https://www.youtube.com/embed/fUEHlY8" width="640"&gt;&lt;/iframe&gt;</p>

So i have checked now a lot of solutions and documentations and nothing is working anymore.

In the TSConfig i have tested now the following solution (and some other) but the output is still escaped. In the RTE i can see the video. In the Editor it's solved and shown with a surrounded p tag.

RTE.default.proc {
  allowTags := addToList(object,param,embed,iframe)
  allowTagsOutside := addToList(object,embed,iframe)
  entryHTMLparser_db.allowTags < .allowTags
}

We have some different sites with the same code and structure and in all pages the same problem appears and the iframe and youtube video is not shown and visible as text.