CVE-2026-46428

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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/lettre/lettre/commit/f5efffc88360dbdbfcef80f465e42d5bce68ca35
https://github.com/lettre/lettre/releases/tag/v0.11.22
https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53
https://rustsec.org/advisories/RUSTSEC-2026-0141.html
https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53

Configurations

No configuration.

History

21 Jul 2026, 16:17

Type	Values Removed	Values Added
References	~~() https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53 -~~	() https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53 -

20 Jul 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-20 16:17

Updated : 2026-07-23 17:58

NVD link : CVE-2026-46428

Mitre link : CVE-2026-46428

CVE.ORG link : CVE-2026-46428

JSON object : View

Products Affected

No product.

CWE

CWE-295

Improper Certificate Validation

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