TYPO3 Core

I stumbled about a really hard to spot but serious issue regarding this change. When you use config.linkVars = L, then it is possible to globally override the target language of all links on a page by adding the L Parameter to the URL.

Example scenario: (TYPO3 9.5 - master)

• Website has 2 languages (0 = DE and 1 = EN)
• TYPO3 page cache is empty
• Website is initially opened as https://website.tld/?L=1

Result:

• The website is shown in german language (expected) but all links created by PageLinkBuilder will link to the english version of the target (not expected).

Removing the L parameter from config.linkVars resolved the problem.

Should the L parameter from GET vars really be taken into account for language settings in TYPO3 9.5+?