Affected versions of Flowintel incorrectly attempted to validate login email addresses by calling Email(email). That does not perform WTForms field validation; it merely constructs a validator object.
Consequently, malformed attacker-controlled email input could continue through the login process and be written to security-relevant logs. The vulnerable code inserted the supplied email into both a warning log and the custom audit logger. Since CR/LF characters were not escaped, an unauthenticated attacker could potentially inject additional physical log lines or forge misleading log entries.
The patch corrects the validation call to Email()(form, form.email), changes the standard logging call to parameterized logging, and introduces _sanitize_log_fragment() so carriage returns and line feeds are encoded instead of creating new records.