# lettre (crates.io) vulnerabilities

3 known vulnerabilities (1 critical), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: 0.11.23 (Aug 3, 2026): no advisory affects it
- Newest unaffected release: 0.11.23 (Aug 3, 2026), the latest release
- Weekly downloads: 661.8K
- Dependents: 21
- Releases: 65 since 0.4.0 (Oct 21, 2015)
- Registry: https://crates.io/crates/lettre
- Releases read: Nov 8, 2026

## Version timeline

Affected versions per advisory, in version order:

- CVE-2026-46428: 0.10.1 to 0.11.21 (0.11.22 is outside it)
- CVE-2021-38189: 0.7.0 to 0.9.5 (0.9.6 is outside it); 0.10.0-alpha.1 to 0.10.0-rc.2 (0.10.0-rc.3 is outside it)
- CVE-2020-28247: 0.7.0 (0.7.1 is outside it); 0.8.0 to 0.8.3 (0.8.4 is outside it); 0.9.0 to 0.9.3 (0.9.5 is outside it); 0.10.0-alpha.1 to 0.10.0-alpha.3 (0.10.0-alpha.4 is outside it)

## Advisories (3)

### [CVE-2026-46428](https://cve.now/CVE-2026-46428): lettre has TLS hostname verification disabled when using Boring TLS backend

- Severity: Critical 9.1
- Published: Jul 20, 2026
- Affected: from 0.10.1, fixed in 0.11.22.
- Fixed in 0.11.22 (released May 14, 2026, 67 days before disclosure).
- The latest release, 0.11.23, is not affected.

### [CVE-2021-38189](https://cve.now/CVE-2021-38189): An issue was discovered in the lettre crate before 0.9.6 for Rust.

- Severity: Unrated
- Published: Aug 8, 2021
- Affected: from 0.7.0, fixed in 0.9.6; from 0.10.0-alpha.1, fixed in 0.10.0-rc.3; from 0.7.0, fixed in 0.9.6.
- Fixed in 0.9.6 (released May 22, 2021, 78 days before disclosure) and 0.10.0-rc.3 (released May 22, 2021, 78 days before disclosure).
- The latest release, 0.11.23, is not affected.

### [CVE-2020-28247](https://cve.now/CVE-2020-28247): The lettre library through 0.10.0-alpha for Rust allows arbitrary sendmail option injection via transport/sendmail/mod.rs.

- Severity: Unrated
- Published: Nov 12, 2020
- Affected: from 0.9.0, fixed in 0.9.5; from 0.8.0, fixed in 0.8.4; from 0.7.0, fixed in 0.7.1; from 0.7.0, fixed in 0.7.1; from 0.8.0, fixed in 0.8.4; from 0.9.0, fixed in 0.9.5; from 0.10.0-alpha.1, fixed in 0.10.0-alpha.4.
- Fixed in 0.7.1 (released Nov 11, 2020, 1 day before disclosure), 0.8.4 (released Nov 11, 2020, 1 day before disclosure), 0.9.5 (released Nov 11, 2020, 1 day before disclosure) and 1 other version.
- The latest release, 0.11.23, is not affected.

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