{
  "document": {
    "aggregate_severity": {
      "text": "Medium"
    },
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "TuxCare License Agreement",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.",
        "title": "Terms of Use"
      }
    ],
    "publisher": {
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      "contact_details": "https://tuxcare.com/contact/",
      "name": "TuxCare",
      "namespace": "https://tuxcare.com/"
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        "category": "self",
        "summary": "Canonical URL",
        "url": "https://security.tuxcare.com/csaf/v2/els_os/oraclelinux7els/vex/2021/cve-2021-3672-els_os-oraclelinux7els.json"
      }
    ],
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      "current_release_date": "2026-04-20T08:48:55Z",
      "generator": {
        "date": "2026-04-20T08:48:55Z",
        "engine": {
          "name": "pyCSAF"
        }
      },
      "id": "CVE-2021-3672-ELS_OS-ORACLELINUX7ELS",
      "initial_release_date": "2021-11-23T19:15:00Z",
      "revision_history": [
        {
          "date": "2021-11-23T19:15:00Z",
          "number": "1",
          "summary": "Initial version"
        },
        {
          "date": "2026-04-20T08:48:55Z",
          "number": "2",
          "summary": "Official Publication"
        }
      ],
      "status": "final",
      "version": "2"
    },
    "title": "Security update on CVE-2021-3672"
  },
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  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-3672",
      "cwe": {
        "id": "CWE-79",
        "name": "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"
      },
      "notes": [
        {
          "category": "description",
          "text": "A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "known_affected": [
          "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.i686",
          "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
          "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
          "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.x86_64",
          "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.i686",
          "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
          "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
          "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.x86_64"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2021-3672"
        },
        {
          "category": "external",
          "summary": "https://bugzilla.redhat.com/show_bug.cgi?id=1988342",
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1988342"
        },
        {
          "category": "external",
          "summary": "https://c-ares.haxx.se/adv_20210810.html",
          "url": "https://c-ares.haxx.se/adv_20210810.html"
        },
        {
          "category": "external",
          "summary": "https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf",
          "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf"
        },
        {
          "category": "external",
          "summary": "https://security.gentoo.org/glsa/202401-02",
          "url": "https://security.gentoo.org/glsa/202401-02"
        },
        {
          "category": "external",
          "summary": "https://www.oracle.com/security-alerts/cpujul2022.html",
          "url": "https://www.oracle.com/security-alerts/cpujul2022.html"
        }
      ],
      "release_date": "2021-11-23T19:15:00Z",
      "remediations": [
        {
          "category": "no_fix_planned",
          "details": "This issue requires an attacker to inject a non‑compliant DNS reply (a CNAME containing an embedded NUL byte) to a client specifically using c‑ares, making exploitation high‑complexity and yielding no code execution with only low confidentiality, integrity, and availability impact. c‑ares itself does not cache DNS answers, so any misparsed hostname is transient unless an application has built its own cache and blindly trusts the returned string. Only c‑ares versions up to 1.17.1 are affected; 1.17.2 and newer are not exposed.",
          "product_ids": [
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.i686",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.x86_64",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.i686",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.x86_64"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v2": {
            "accessComplexity": "MEDIUM",
            "accessVector": "NETWORK",
            "authentication": "NONE",
            "availabilityImpact": "PARTIAL",
            "baseScore": 6.8,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "PARTIAL",
            "integrityImpact": "PARTIAL",
            "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:P",
            "version": "2.0"
          },
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.6,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L",
            "version": "3.1"
          },
          "products": [
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.i686",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
            "Oracle-Linux-7:c-ares-0:1.10.0-3.el7_9.1.x86_64",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.i686",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.i686",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.tuxcare.els2.x86_64",
            "Oracle-Linux-7:c-ares-devel-0:1.10.0-3.el7_9.1.x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Moderate"
        }
      ]
    }
  ]
}