All versions of package fast-string-search are vulnerable to Out-of-bounds Read due to incorrect memory freeing and length calculation for any non-string input as the source. This allows the attacker to read previously allocated memory.
CWE-125 - Out-of-Bounds Read
Out-of-bounds read is a vulnerability that allows access to memory beyond the authorized accessible location. Such a vulnerability compromises the confidentiality of the trusted environment in the application and enables an attacker to launch further attacks by leveraging the exposed information.