GHSA-5jfw-gq64-q45f
Vulnerability from github
Published
2024-11-19 21:07
Modified
2025-01-14 16:37
Severity ?
7.7 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H
Summary
HTML Cleaner allows crafted scripts in special contexts like svg or math to pass through
Details

Impact

The HTML Parser in lxml does not properly handle context-switching for special HTML tags such as <svg>, <math> and <noscript>. This behavior deviates from how web browsers parse and interpret such tags. Specifically, content in CSS comments is ignored by lxml_html_clean but may be interpreted differently by web browsers, enabling malicious scripts to bypass the cleaning process. This vulnerability could lead to Cross-Site Scripting (XSS) attacks, compromising the security of users relying on lxml_html_clean in default configuration for sanitizing untrusted HTML content.

Patches

Users employing the HTML cleaner in a security-sensitive context should upgrade to lxml 0.4.0, which addresses this issue.

Workarounds

As a temporary mitigation, users can configure lxml_html_clean with the following settings to prevent the exploitation of this vulnerability: * remove_tags: Specify tags to remove - their content is moved to their parents' tags. * kill_tags: Specify tags to be removed completely. * allow_tags: Restrict the set of permissible tags, excluding context-switching tags like <svg>, <math> and <noscript>.

References

  • https://github.com/fedora-python/lxml_html_clean/pull/19
  • https://github.com/fedora-python/lxml_html_clean/pull/19/commits/c5d816f86eb3707d72a8ecf5f3823e0daa1b3808
Show details on source website

To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lxml-html-clean"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-52595"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-184",
      "CWE-79",
      "CWE-83"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-11-19T21:07:59Z",
    "nvd_published_at": "2024-11-19T22:15:21Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nThe HTML Parser in lxml does not properly handle context-switching for special HTML tags such as `\u003csvg\u003e`, `\u003cmath\u003e` and `\u003cnoscript\u003e`. This behavior deviates from how web browsers parse and interpret such tags. Specifically, content in CSS comments is ignored by lxml_html_clean but may be interpreted differently by web browsers, enabling malicious scripts to bypass the cleaning process. This vulnerability could lead to Cross-Site Scripting (XSS) attacks, compromising the security of users relying on lxml_html_clean in default configuration for sanitizing untrusted HTML content.\n\n### Patches\n\nUsers employing the HTML cleaner in a security-sensitive context should upgrade to lxml 0.4.0, which addresses this issue.\n\n### Workarounds\n\nAs a temporary mitigation, users can configure lxml_html_clean with the following settings to prevent the exploitation of this vulnerability:\n* `remove_tags`: Specify tags to remove - their content is moved to their parents\u0027 tags.\n* `kill_tags`: Specify tags to be removed completely.\n* `allow_tags`: Restrict the set of permissible tags, excluding context-switching tags like `\u003csvg\u003e`, `\u003cmath\u003e` and `\u003cnoscript\u003e`.\n\n### References\n\n* https://github.com/fedora-python/lxml_html_clean/pull/19\n* https://github.com/fedora-python/lxml_html_clean/pull/19/commits/c5d816f86eb3707d72a8ecf5f3823e0daa1b3808\n",
  "id": "GHSA-5jfw-gq64-q45f",
  "modified": "2025-01-14T16:37:30Z",
  "published": "2024-11-19T21:07:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-5jfw-gq64-q45f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-52595"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fedora-python/lxml_html_clean/pull/19"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fedora-python/lxml_html_clean/commit/c5d816f86eb3707d72a8ecf5f3823e0daa1b3808"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fedora-python/lxml_html_clean"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml-html-clean/PYSEC-2024-160.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "HTML Cleaner allows crafted scripts in special contexts like svg or math to pass through"
}


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