Rust up to 0.11.21 boring-tls certificate validation

Summaryinfo

A vulnerability has been found in Rust up to 0.11.21 and classified as problematic. This affects an unknown part of the component boring-tls. This manipulation causes certificate validation. This vulnerability is registered as CVE-2026-46428. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Rust up to 0.11.21. It has been declared as problematic. Affected by this vulnerability is an unknown part of the component boring-tls. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-46428 since 05/14/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

Upgrading to version 0.11.22 eliminates this vulnerability.

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Productinfo

Name

• Rust

Version

• 0.11.0
• 0.11.1
• 0.11.2
• 0.11.3
• 0.11.4
• 0.11.5
• 0.11.6
• 0.11.7
• 0.11.8
• 0.11.9
• 0.11.10
• 0.11.11
• 0.11.12
• 0.11.13
• 0.11.14
• 0.11.15
• 0.11.16
• 0.11.17
• 0.11.18
• 0.11.19
• 0.11.20
• 0.11.21

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CPE 2.2info

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