sqlite3-ruby has Use-After-Free When Redefining SQLite Functions with Different Arity

Summary

Using Database#create_function or Database#define_function to define the same function name more than once with different numbers of arguments ("arity") or text encodings will result in a invalid memory read and a segmentation fault.

Mitigation

Upgrade to sqlite3 gem v2.9.5 or later.

As a workaround, avoid defining multiple custom functions with the same name (varying numbers of arguments or encoding).

Severity

The sqlite3-ruby maintainers assess this as Low severity. It is reliably triggered after GC when code is structured in a particular way. There is no known general exploit that could be used as a denial of service attack.