TYPO3 Core

e.g in typo3/mod/tools/em/index.php, line 2665
if (ereg('^class[[:space:]]*([[:alnum:]_]+)([[:alnum:][:space:]_]*){',$line,$reg)) {

results in an error in an installation with PHP 4.3.3 (reported by Thomas Ludescher on the Austrian TYPO3 mailinglist)
There are other occurences of unescaped curly braces in regular expressions all over the TYPO3 source code.

Curly braces have a special meaning in regular expressions and should therefore be escaped with a backslash "\" IMHO

TYPO3 3.7, 3.8(CVS)
(issue imported from #M1043)