TYPO3 Core

I have a site with the url "http://blabla/index.php". There are 2 languages. If i enter
"http://blabla/index.php?id=10&L=1" or L=2 or L=0 everything is ok but if i enter "http://blabla/index.php?id=10&L=1sometext" or
"http://blabla/index.php?id=10&L=124" the page 10 will be cached with L=0 but all links and the navigation will have als parameter the L from URL so on my site i have links
http://blabla/index.php?id=10&L=1robots.txt or
http://blabla/index.php?id=10&L=12345 ewen if the L=12345 not exists. (Just because someone has visited my page and has try to use this parameters and he has visited some pages which was not at that time in cache)

I have solved it with this patch:
file /typo3/sysext/cms/tslib/index_ts.php
after
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// ***********************************
// Setting the internal var, sys_language_uid + locale settings
// ***********************************
$TSFE->settingLanguage();
$TSFE->settingLocale();
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just insert
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$_GET['L']=intval($_GET['L']);
$_POST['L']=intval($_POST['L']);
if($_GET['L']==0 || ($_GET['L']>0 && $TSFE->sys_page->sys_language_uid!=$_GET['L'])){unset($_GET['L']);}
if($_POST['L']==0 || ($_POST['L']>0 && $TSFE->sys_page->sys_language_uid!=$_POST['L'])){unset($_POST['L']);}
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(issue imported from #M5878)