FKIE_CVE-2021-47996

Vulnerability from fkie_nvd - Published: 2026-08-25 16:16 - Updated: 2026-08-25 18:17
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.
References
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/1098c30a040e72a4654968547f415be4e4c40fe7
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/1358d157d0bd83be1dfe356a69213df9fac0b539
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/8598060bacada41a0eb09d95c97744ff4e428f8e
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/babe75030c7f64a37826bb3342317134568bef61
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2
disclosure@vulncheck.comhttps://github.com/sparklemotion/nokogiri/security/advisories/GHSA-7rrm-v45f-jp64
disclosure@vulncheck.comhttps://www.vulncheck.com/advisories/nokogiri-before-multiple-vulnerabilities-via-libxml2
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:gem/nokogiri",
          "product": "nokogiri",
          "vendor": "sparklemotion",
          "versions": [
            {
              "lessThan": "1.11.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "1.11.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption."
    }
  ],
  "id": "CVE-2021-47996",
  "lastModified": "2026-08-25T18:17:02.543",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-47996",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-25T17:19:25.611074Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-25T16:16:42.930",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/0e1a49c8907645d2e155f0d89d4d9895ac5112b5"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/1098c30a040e72a4654968547f415be4e4c40fe7"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/1358d157d0bd83be1dfe356a69213df9fac0b539"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/50f06b3efb638efb0abd95dc62dca05ae67882c2"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/7ffcd44d7e6c46704f8af0321d9314cd26e0e18a"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/8598060bacada41a0eb09d95c97744ff4e428f8e"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/babe75030c7f64a37826bb3342317134568bef61"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/commit/bf22713507fe1fc3a2c4b525cf0a88c2dc87a3a2"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-7rrm-v45f-jp64"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/nokogiri-before-multiple-vulnerabilities-via-libxml2"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-119"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Secondary"
    }
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Detection rules are retrieved from Rulezet.