{
  "id": "CVE-2021-42013",
  "url": "https://spydr.io/cve/CVE-2021-42013",
  "published": "2021-10-07T16:15:09.270Z",
  "modified": "2026-06-17T04:09:09.193Z",
  "score": 9.8,
  "severity": "critical",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "score_source": "NVD",
  "epss": 0.99964,
  "epss_percentile": 0.99976,
  "exploited": true,
  "kev": {
    "added": "2021-11-03",
    "due": "2021-11-17",
    "action": "Apply updates per vendor instructions.",
    "ransomware": "Known",
    "name": "Apache HTTP Server Path Traversal Vulnerability",
    "notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-42013"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Apache Software Foundation"
  ],
  "products": [
    "Apache Software Foundation Apache HTTP Server"
  ],
  "cwes": [
    "CWE-22"
  ],
  "description": "It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration \"require all denied\", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.",
  "status": "Analyzed",
  "score_type": "Primary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 9.8,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "http://jvn.jp/en/jp/JVN51106450/index.html",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.html",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/07/6",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/1",
      "tags": [
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        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/2",
      "tags": [
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    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/3",
      "tags": [
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    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/4",
      "tags": [
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    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/5",
      "tags": [
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    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/08/6",
      "tags": [
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    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/09/1",
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    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/11/4",
      "tags": [
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        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/15/3",
      "tags": [
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        "Third Party Advisory"
      ]
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2021/10/16/1",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://httpd.apache.org/security/vulnerabilities_24.html",
      "tags": [
        "Release Notes",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E",
      "tags": [
        "Mailing List",
        "Patch"
      ]
    },
    {
      "url": "https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E",
      "tags": [
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    {
      "url": "https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E",
      "tags": [
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    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://security.gentoo.org/glsa/202208-20",
      "tags": [
        "Third Party Advisory"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2021-42013",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}