FKIE_CVE-2021-32066

Vulnerability from fkie_nvd - Published: 2021-08-01 19:15 - Updated: 2026-06-17 03:52
Severity
7.4 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."
References
cve@mitre.orghttps://github.com/ruby/ruby/commit/a21a3b7d23704a01d34bd79d09dc37897e00922aPatch, Third Party Advisory
cve@mitre.orghttps://hackerone.com/reports/1178562Exploit, Patch, Third Party Advisory
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2021/10/msg00009.htmlThird Party Advisory
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
cve@mitre.orghttps://security.gentoo.org/glsa/202401-27
cve@mitre.orghttps://security.netapp.com/advisory/ntap-20210902-0004/Third Party Advisory
cve@mitre.orghttps://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
cve@mitre.orghttps://www.ruby-lang.org/en/news/2021/07/07/starttls-stripping-in-net-imap/Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/ruby/ruby/commit/a21a3b7d23704a01d34bd79d09dc37897e00922aPatch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://hackerone.com/reports/1178562Exploit, Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/10/msg00009.htmlThird Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202401-27
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20210902-0004/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.ruby-lang.org/en/news/2021/07/07/starttls-stripping-in-net-imap/Vendor Advisory
Impacted products
Vendor Product Version
ruby-lang ruby *
ruby-lang ruby *
ruby-lang ruby *
oracle jd_edwards_enterpriseone_tools *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
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              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
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              "versionEndIncluding": "2.6.7",
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              "vulnerable": true
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a \"StartTLS stripping attack.\""
    },
    {
      "lang": "es",
      "value": "Se ha detectado un problema en Ruby versiones hasta 2.6.7, versiones 2.7.x hasta 2.7.3, y versiones 3.x hasta 3.0.1. Net::IMAP no lanza una excepci\u00f3n cuando StartTLS falla con una respuesta desconocida, lo que podr\u00eda permitir a atacantes tipo man-in-the-middle omitir las protecciones TLS, al aprovechar una posici\u00f3n de red entre el cliente y el registro para bloquear el comando StartTLS, tambi\u00e9n se conoce como \"StartTLS stripping attack\""
    }
  ],
  "id": "CVE-2021-32066",
  "lastModified": "2026-06-17T03:52:44.373",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "MEDIUM",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 5.8,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 8.6,
        "impactScore": 4.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
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          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
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          "scope": "UNCHANGED",
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          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
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        "source": "nvd@nist.gov",
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  "published": "2021-08-01T19:15:07.697",
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  "vulnStatus": "Modified",
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}



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Sightings

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Nomenclature

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