PYSEC-2021-19

Vulnerability from pysec - Published: 2021-03-21 05:15 - Updated: 2021-03-30 18:47
VLAI?
Details

An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.

Impacted products
Name purl
lxml pkg:pypi/lxml
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lxml",
        "purl": "pkg:pypi/lxml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a5f9cb52079dc57477c460dbe6ba0f775e14a999"
            }
          ],
          "repo": "https://github.com/lxml/lxml",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.6.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9",
        "0.9.1",
        "0.9.2",
        "1.0.beta",
        "1.0",
        "1.0.1",
        "1.0.2",
        "1.0.3",
        "1.0.4",
        "1.1alpha",
        "1.1beta",
        "1.1",
        "1.1.1",
        "1.1.2",
        "1.2",
        "1.2.1",
        "1.3beta",
        "1.3",
        "1.3.1",
        "1.3.2",
        "1.3.3",
        "1.3.4",
        "1.3.5",
        "1.3.6",
        "2.0alpha1",
        "2.0alpha2",
        "2.0alpha3",
        "2.0alpha4",
        "2.0alpha5",
        "2.0alpha6",
        "2.0beta1",
        "2.0beta2",
        "2.0",
        "2.0.1",
        "2.0.2",
        "2.0.3",
        "2.0.4",
        "2.0.5",
        "2.0.6",
        "2.0.7",
        "2.0.8",
        "2.0.9",
        "2.0.10",
        "2.0.11",
        "2.1alpha1",
        "2.1beta1",
        "2.1beta2",
        "2.1beta3",
        "2.1",
        "2.1.1",
        "2.1.2",
        "2.1.3",
        "2.1.4",
        "2.1.5",
        "2.2alpha1",
        "2.2beta1",
        "2.2beta2",
        "2.2beta3",
        "2.2beta4",
        "2.2",
        "2.2.1",
        "2.2.2",
        "2.2.3",
        "2.2.4",
        "2.2.5",
        "2.2.6",
        "2.2.7",
        "2.2.8",
        "2.3alpha1",
        "2.3alpha2",
        "2.3beta1",
        "2.3",
        "2.3.1",
        "2.3.2",
        "2.3.3",
        "2.3.4",
        "2.3.5",
        "2.3.6",
        "3.0",
        "3.0.1",
        "3.0.2",
        "3.1beta1",
        "3.1.0",
        "3.1.1",
        "3.1.2",
        "3.2.0",
        "3.2.1",
        "3.2.2",
        "3.2.3",
        "3.2.4",
        "3.2.5",
        "3.3.0beta1",
        "3.3.0beta2",
        "3.3.0beta3",
        "3.3.0beta4",
        "3.3.0beta5",
        "3.3.0",
        "3.3.1",
        "3.3.2",
        "3.3.3",
        "3.3.4",
        "3.3.5",
        "3.3.6",
        "3.4.0",
        "3.4.1",
        "3.4.2",
        "3.4.3",
        "3.4.4",
        "3.5.0b1",
        "3.5.0",
        "3.6.0",
        "3.6.1",
        "3.6.2",
        "3.6.3",
        "3.6.4",
        "3.7.0",
        "3.7.1",
        "3.7.2",
        "3.7.3",
        "3.8.0",
        "4.0.0",
        "4.1.0",
        "4.1.1",
        "4.2.0",
        "4.2.1",
        "4.2.2",
        "4.2.3",
        "4.2.4",
        "4.2.5",
        "4.2.6",
        "4.3.0",
        "4.3.1",
        "4.3.2",
        "4.3.3",
        "4.3.4",
        "4.3.5",
        "4.4.0",
        "4.4.1",
        "4.4.2",
        "4.4.3",
        "4.5.0",
        "4.5.1",
        "4.5.2",
        "4.6.0",
        "4.6.1",
        "4.6.2"
      ]
    }
  ],
  "aliases": [
    "CVE-2021-28957",
    "GHSA-jq4v-f5q6-mjqq"
  ],
  "details": "An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.",
  "id": "PYSEC-2021-19",
  "modified": "2021-03-30T18:47:00Z",
  "published": "2021-03-21T05:15:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://bugs.launchpad.net/lxml/+bug/1888153"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
    },
    {
      "type": "FIX",
      "url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.debian.org/security/2021/dsa-4880"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
    }
  ]
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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