The be_user_creation task in TYPO3 4.2.x before 4.2.15 and 4.3.x before 4.3.7 allows remote authenticated users to gain privileges via a crafted POST request that creates a user account with arbitrary group memberships.
Exploitability
AV:NAC:MAu:SImpact
C:PI:PA:P6/AV:N/AC:M/Au:S/C:P/I:P/A:P