Insufficient checks in the UDF subsystem in Firebird 2.5.x before 2.5.7 and 3.0.x before 3.0.2 allow remote authenticated users to execute code by using a 'system' entrypoint from fbudf.so.

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when deserializing a slice packet, the xdrdatum() function does not validate that a cstring length conforms to the slice descriptor bounds, allowing a cstring longer than the allocated buffer to overflow it. An unauthenticated attacker can exploit this by sending a crafted packet to the server, potentially causing a crash or other security impact. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the xdrstatusvector() function does not handle the iscargcstring type when decoding an opresponse packet, causing a server crash when one is encountered in the status vector. An unauthenticated attacker can exploit this by sending a crafted opresponse packet to the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the sdldesc() function does not validate the length of a decoded SDL descriptor from a slice packet. A zero-length descriptor is later used to calculate the number of slice items, causing a division by zero. An unauthenticated attacker can exploit this by sending a crafted slice packet to crash the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.