```toml
[advisory]
id = "RUSTSEC-2021-0069"
package = "lettre"
date = "2021-05-22"
url = "https://github.com/lettre/lettre/pull/627/commits/93458d01fed0ec81c0e7b4e98e6f35961356fae2"
categories = ["format-injection"]
keywords = ["email", "smtp"]
aliases = ["GHSA-qc36-q22q-cjw3", "CVE-2021-38189"]

[versions]
patched = [">= 0.10.0-rc.3", "< 0.10.0-alpha.1, >= 0.9.6"]
unaffected = ["< 0.7.0"]

[affected.functions]
# smtp transport
"lettre::smtp::SmtpTransport::send" = ["< 0.10.0-alpha.1"]
"lettre::transport::smtp::SmtpTransport::send" = [">= 0.10.0-alpha.1, < 0.10.0-rc.3"]
"lettre::transport::smtp::SmtpTransport::send_raw" = [">= 0.10.0-alpha.1, < 0.10.0-rc.3"]
```

# SMTP command injection in body

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.