PHP 4.4.2 and 5.1.2 allows local users to cause a crash (segmentation fault) by defining and executing a recursive function. NOTE: it has been reported by a reliable third party that some later versions are also affected.
Exploitability
AV:LAC:LAu:NImpact
C:NI:NA:P2.1/AV:L/AC:L/Au:N/C:N/I:N/A:P