TYPO3 Core

When using t3lib_cs->utf8_decode() to decoding an utf8 string to another charset the function does not check whether the target charset is utf8. This can lead to scrambled content.

This can especially happen with backends running as utf8.

With kickstarter create a new extension containing a table with a single field f.e.. Then go to view result, you'll notice that the content for the locallang_db.xml file is not shown when running in a utf8 backend. This is because the content got scrambled.

A simple check for the target charset being utf8 solves the problem, the string can then be returned as is.
(issue imported from #M10838)