Affected versions of lettre allowed SMTP command injection through an attacker's controlled message body. The module for escaping lines starting with a period wouldn't catch a period that was placed after a double CRLF sequence, allowing the attacker to end the current message and write arbitrary SMTP commands after it.
The flaw is fixed by correctly handling consecutive CRLF sequences.
{ "nvd_published_at": "2021-08-08T06:15:00Z", "github_reviewed_at": "2021-06-01T20:41:39Z", "severity": "CRITICAL", "github_reviewed": true, "cwe_ids": [ "CWE-147" ] }