RUSTSEC-2026-0141

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Source

https://rustsec.org/advisories/RUSTSEC-2026-0141

Import Source

https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0141.json

JSON Data

https://api.osv.dev/v1/vulns/RUSTSEC-2026-0141

Aliases

GHSA-4pj9-g833-qx53

Published

2026-05-14T12:00:00Z

Modified

2026-05-14T09:15:06.684884Z

Severity

9.1 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N CVSS Calculator

Summary

TLS hostname verification disabled when using Boring TLS backend

Details

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.

The bug was introduced in v0.10.1 and persists through v0.11.21 (latest).

Database specific

{
    "license": "CC0-1.0"
}

References

Affected packages

crates.io / lettre

Package

Name: lettre; View open source insights on deps.dev
Purl: pkg:cargo/lettre

Affected ranges

Type: SEMVER
Events: Introduced

0.10.1

Fixed

0.11.22

Ecosystem specific

{
    "affected_functions": null,
    "affects": {
        "functions": [],
        "arch": [],
        "os": []
    }
}

Database specific

source

"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0141.json"

informational

null