Description (CNA)
lettre is a a mailer library for Rust. Starting in version 0.10.1 and prior to version 0.11.22, an inverted-boolean bug in lettre's `boring-tls` integration silently disables TLS hostname verification for callers using the default (strict) configuration. An on-path attacker presenting any chain-valid certificate for any domain can intercept SMTP submission, including PLAIN/LOGIN credentials and message contents, against any lettre user built with the `boring-tls` feature. Other TLS backends (`native-tls`, `rustls`) are unaffected. Version 0.11.22 patches the issue.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| lettre / lettre | affected >= 0.10.1, < 0.11.22 |
CWE
CWE-295
References
- https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53
- https://github.com/lettre/lettre/commit/f5efffc88360dbdbfcef80f465e42d5bce68ca35
- https://github.com/lettre/lettre/releases/tag/v0.11.22
- https://rustsec.org/advisories/RUSTSEC-2026-0141.html
ADP enrichment
No English description supplied.