Improper Certificate Validation Affecting lettre package, versions >=0.10.1 <0.11.22
Threat Intelligence
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The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RUST-LETTRE-18307390
- published25 Jul 2026
- disclosed20 Jul 2026
- creditUnknown
Introduced: 20 Jul 2026
NewCVE-2026-46428 (opens in a new tab)How to fix?
Upgrade lettre to version 0.11.22 or higher.
Overview
lettre is a mailer library for Rust.
Affected versions of this package are vulnerable to Improper Certificate Validation due to TLS hostname verification being disabled in the boring-tls integration. An attacker can intercept SMTP submissions and access sensitive information, such as credentials and message contents, by presenting a chain-valid certificate for any domain.