The privateaddresscheck ruby gem before 0.5.0 is vulnerable to a time-of-check time-of-use (TOCTOU) race condition due to the address the socket uses not being checked. DNS entries with a TTL of 0 can trigger this case where the initial resolution is a public address but the subsequent resolution is a private address.
{ "nvd_published_at": null, "cwe_ids": [ "CWE-362" ], "severity": "HIGH", "github_reviewed": true, "github_reviewed_at": "2020-06-16T20:53:26Z" }