src/remote/server.cpp in fbserver.exe in Firebird SQL 1.5 before 1.5.6, 2.0 before 2.0.6, 2.1 before 2.1.3, and 2.5 before 2.5 Beta 2 allows remote attackers to cause a denial of service (daemon crash) via a malformed op_connect_request message that triggers an infinite loop or NULL pointer dereference.

Multiple stack-based buffer overflows in Firebird LI 1.5.3.4870 and 1.5.4.4910, and WI 1.5.3.4870 and 1.5.4.4910, allow remote attackers to execute arbitrary code via (1) a long service attach request on TCP port 3050 to the SVC_attach function or (2) unspecified vectors involving the INET_connect function.