{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.16.0"
              },
              {
                "fixed": "1.17.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "DESCRIPTION"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "273422f9f8a1b87cb1c13d892b50d3e42141d4e8"
            }
          ],
          "repo": "https://github.com/emilstenstrom/justhtml",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-vrx2-77f2-ww34"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6827.json"
  },
  "details": "justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces (SVG/MathML), dangerous content such as HTML integration points (SVG \u003cforeignObject\u003e, MathML \u003cannotation-xml encoding=\"text/html\"\u003e) and mutation-XSS parser-differential payloads could survive sanitization and become active HTML after reparse; SVG filter=\"url(...)\" and preserved \u003cstyle\u003e could leave resource-loading CSS (@import, background-image:url()). Programmatic script/style/Comment nodes could serialize into active markup. Additional hardening fixes address sanitize-pipeline cache mutation and DOM parent/child cycles that could cause infinite loops. Most issues affect advanced or custom configurations rather than the default JustHTML(..., sanitize=True) safe path.",
  "id": "CVE-2026-6827",
  "modified": "2026-08-25T03:51:42.837019738Z",
  "published": "2026-08-23T13:34:11.236Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6827.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-vrx2-77f2-ww34"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6827"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/justhtml-before-multiple-cross-site-scripting-vulnerabilities"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "justhtml before 1.17.0 Multiple Cross-Site Scripting Vulnerabilities"
}