Vulnerability MediumRUSTSEC-2020-0069 · lettre
RUSTSEC-2020-0069: Argument injection in sendmail transport
Short answerA security vulnerability in the lettre crate: Argument injection in sendmail transport. Medium severity (CVSS 5.3). Fixed in 0.10.0-alpha.4, 0.7.1, 0.8.4, 0.9.5: update to a fixed version.
| Crate | lettre |
|---|---|
| Type | Vulnerability (code-execution, file-disclosure) |
| Affected versions | From 0.7.0 before 0.7.1; from 0.8.0 before 0.8.4; from 0.9.0 before 0.9.5; from 0.10.0-alpha.1 before 0.10.0-alpha.4. |
| Fixed in | 0.10.0-alpha.4, 0.7.1, 0.8.4, 0.9.5 |
| Severity | Medium, CVSS 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| Published | 2020-11-11 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2020-28247, GHSA-vc2p-r46x-m3vx |
| Affected functions | lettre::sendmail::SendmailTransport::send, lettre::transport::sendmail::SendmailTransport::send, lettre::transport::sendmail::SendmailTransport::send_raw |
What to do
- See which version you have:
cargo tree -i lettre(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p lettre. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for examplelettre = "0.9.5") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
Affected versions of lettre allowed argument injection to the sendmail command. It was possible, using forged to addresses, to pass arbitrary arguments to the sendmail executable.
Depending on the implementation (original sendmail, postfix, exim, etc.) it could be possible in some cases to write email data into arbitrary files (using sendmail's logging features).
The flaw is corrected by modifying the executed command to stop parsing arguments before passing the destination addresses.
NOTE: This vulnerability only affects the sendmail transport. Others, including smtp, are not affected.
This vulnerability was reported by vin01.
References
- Package: crates.io/crates/lettre
- Advisory: rustsec.org/advisories/RUSTSEC-2020-0069.html
- Web: github.com/lettre/lettre/pull/508/commits/bbe7cc5381c5380b54fb8bbb4f77a3725917ff0b
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for lettre
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