An unspecified vulnerability was found in FireBird. By exploiting this vulnerability malicious users can cause denial of service. This vulnerability can be exploited remotely via a specially designed message.

FireBird SQL 1.5 versions 1.5.5 and earlier
FireBird SQL 2.0 versions 2.0.5 and earlier
FireBird SQL 2.1 versions 2.1.2 and earlier
FireBird SQL 2.5 versions beta 1 and earlier

Update to latest version
FireBird SQL