TYPO3 Core

In some configuratins there are error messages like "Unable to parse URL" in the logfile. This is because tslib_fe->checkAlternativeIdMethods() calls parse_url($this->siteScript). This works in most cases, but not if wrong urls with // like http://domain.tld//path are requested. We had this in our logfiles caused by scripts searching for security vulnerabilities.
The simple solution is to add TYPO3_SITE_URL to make sure parse_url() gets a valid url.

(issue imported from #M11778)