{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.10.1"
              },
              {
                "fixed": "0.11.22"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0c9fc6cb71650e49abc37540a48ffcbc2fe38ee4"
            },
            {
              "fixed": "f5efffc88360dbdbfcef80f465e42d5bce68ca35"
            },
            {
              "fixed": "9b88c4ff98fd8653cb389a66f885f02efd79ee6b"
            }
          ],
          "repo": "https://github.com/lettre/lettre",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4pj9-g833-qx53"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-295"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46428.json"
  },
  "details": "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.",
  "id": "CVE-2026-46428",
  "modified": "2026-07-23T03:56:34.707274681Z",
  "published": "2026-07-20T15:37:58.396Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/lettre/lettre/releases/tag/v0.11.22"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46428.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46428"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0141.html"
    },
    {
      "type": "FIX",
      "url": "https://github.com/lettre/lettre/commit/f5efffc88360dbdbfcef80f465e42d5bce68ca35"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "lettre has TLS hostname verification disabled when using Boring TLS backend"
}