BREW-MCP-ATLASSIAN-CVE-2… (GHSA-JQ4V-F5Q6-MJQQ)

Vulnerability from osv_homebrew – Published: 2026-08-13 17:13 – Updated: 2026-09-10 00:30 – Source website
VLAI
Summary
lxml vulnerable to Cross-Site Scripting
Details

An XSS vulnerability was discovered in the python lxml 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.

Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "lxml",
        "resource_purl": "pkg:pypi/lxml@6.1.1",
        "upstream_fixed_in": "4.6.3"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "mcp-atlassian",
        "purl": "pkg:brew/mcp-atlassian"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.23.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/lxml@6.1.1",
        "name": "lxml",
        "resource": "lxml",
        "strategy": "registry",
        "subject_version": "6.1.1"
      }
    ]
  },
  "details": "An XSS vulnerability was discovered in the python `lxml` 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": "BREW-mcp-atlassian-CVE-2021-28957",
  "modified": "2026-09-10T00:30:25Z",
  "published": "2026-08-13T17:13:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-28957"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/pull/316"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
    },
    {
      "type": "WEB",
      "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2021/dsa-4880"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20210521-0004"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202208-06"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/lxml"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/lxml/lxml"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-jq4v-f5q6-mjqq"
    },
    {
      "type": "WEB",
      "url": "https://bugs.launchpad.net/lxml/+bug/1888153"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "lxml vulnerable to Cross-Site Scripting ",
  "upstream": [
    "GHSA-jq4v-f5q6-mjqq",
    "CVE-2021-28957",
    "PYSEC-2021-19"
  ]
}



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