SAP Adaptive Server Enterprise (ASE) 15.7 before SP122 or SP63, 15.5 before ESD#5.4, and 15.0.3 before ESD#4.4 does not properly restrict access, which allows remote authenticated database users to (1) overwrite the master encryption key or (2) trigger a buffer overflow via a crafted RPC message to the hacmpmsgxchg function, and possibly other vectors.