Integer overflow in Firebird 2.0.0 allows remote authenticated users to cause a denial of service (CPU consumption) via certain database operations with multi-byte character sets that trigger an attempt to use the value 65536 for a 16-bit integer, which is treated as 0 and causes an infinite loop on zero-length data.
http://www.securityfocus.com/bid/28473
http://www.firebirdsql.org/rlsnotes/Firebird-2.0.1-ReleaseNotes.pdf
http://www.debian.org/security/2008/dsa-1529
http://tracker.firebirdsql.org/browse/CORE-1063