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ubuntu-cve-2021-43818
Vulnerability from osv_ubuntu
Published
2021-12-13 18:15
Modified
2025-09-08 16:47
Summary
Details

lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.

Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
8.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python-lxml",
            "binary_version": "3.3.3-1ubuntu0.2+esm5"
          },
          {
            "binary_name": "python3-lxml",
            "binary_version": "3.3.3-1ubuntu0.2+esm5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "lxml",
        "purl": "pkg:deb/ubuntu/lxml@3.3.3-1ubuntu0.2+esm5?arch=source\u0026distro=trusty/esm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.3.3-1ubuntu0.2+esm5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.0-1",
        "3.3.0~beta2-1",
        "3.3.0~beta4-1",
        "3.3.1-1",
        "3.3.2-1",
        "3.3.2-1build1",
        "3.3.3-1",
        "3.3.3-1ubuntu0.1",
        "3.3.3-1ubuntu0.2",
        "3.3.3-1ubuntu0.2+esm1",
        "3.3.3-1ubuntu0.2+esm2",
        "3.3.3-1ubuntu0.2+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "python-lxml",
            "binary_version": "3.5.0-1ubuntu0.4+esm2"
          },
          {
            "binary_name": "python3-lxml",
            "binary_version": "3.5.0-1ubuntu0.4+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "lxml",
        "purl": "pkg:deb/ubuntu/lxml@3.5.0-1ubuntu0.4+esm2?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.5.0-1ubuntu0.4+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.4-1",
        "3.5.0-1",
        "3.5.0-1build1",
        "3.5.0-1ubuntu0.1",
        "3.5.0-1ubuntu0.2",
        "3.5.0-1ubuntu0.3",
        "3.5.0-1ubuntu0.4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python-lxml",
            "binary_version": "4.2.1-1ubuntu0.6"
          },
          {
            "binary_name": "python3-lxml",
            "binary_version": "4.2.1-1ubuntu0.6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "lxml",
        "purl": "pkg:deb/ubuntu/lxml@4.2.1-1ubuntu0.6?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.2.1-1ubuntu0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.0.0-1",
        "4.1.0-1",
        "4.2.0-1",
        "4.2.1-1",
        "4.2.1-1ubuntu0.1",
        "4.2.1-1ubuntu0.2",
        "4.2.1-1ubuntu0.3",
        "4.2.1-1ubuntu0.4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python-lxml",
            "binary_version": "4.5.0-1ubuntu0.5"
          },
          {
            "binary_name": "python3-lxml",
            "binary_version": "4.5.0-1ubuntu0.5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "lxml",
        "purl": "pkg:deb/ubuntu/lxml@4.5.0-1ubuntu0.5?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.5.0-1ubuntu0.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.4.1-1",
        "4.4.1-1build1",
        "4.4.2-1",
        "4.5.0-1",
        "4.5.0-1ubuntu0.1",
        "4.5.0-1ubuntu0.2",
        "4.5.0-1ubuntu0.3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "python3-lxml",
            "binary_version": "4.7.1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "lxml",
        "purl": "pkg:deb/ubuntu/lxml@4.7.1-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.7.1-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.6.3+dfsg-0.1",
        "4.6.4-1",
        "4.6.4-1ubuntu1"
      ]
    }
  ],
  "aliases": [],
  "details": "lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.",
  "id": "UBUNTU-CVE-2021-43818",
  "modified": "2025-09-08T16:47:25Z",
  "published": "2021-12-13T18:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-43818"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5225-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-43818"
    }
  ],
  "related": [
    "USN-5225-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-43818"
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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