{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.3.1"
              },
              {
                "fixed": "1.5.3"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "088f92b18a4a3911a862b527d5eb3713f9abac24"
            },
            {
              "fixed": "f25255c82a3c6034a57d934718e10c982d29fa31"
            },
            {
              "fixed": "bec27fec4de99e40c68c4285a610e09e791a3eaf"
            }
          ],
          "repo": "https://github.com/rrrene/html_sanitize_ex",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-xmm9-jc22-rcgj"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-829"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66843.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "8976d64ea0b77d26093a94a43ec48a3978e8d028"
          },
          {
            "fixed": "bec27fec4de99e40c68c4285a610e09e791a3eaf"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the data attribute of an \u003cobject\u003e element in sanitized HTML. object is the one URI-bearing element in lib/html_sanitize_ex/scrubber/html5.ex never registered through allow_tag_with_uri_attributes/3, and its only guard is a prefix match on lowercase \"javascript:\", so mixed-case variants, data: URIs, protocol-relative URLs and same-origin paths all survive.\n\nThis is not unconditional cross-site scripting. A javascript: URL does not execute through \u003cobject data\u003e in current browsers, data: documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.",
  "id": "CVE-2026-66843",
  "modified": "2026-08-12T03:51:28.114010955Z",
  "published": "2026-08-06T14:48:20.513Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-66843.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-66843"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66843.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-xmm9-jc22-rcgj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66843"
    },
    {
      "type": "FIX",
      "url": "https://github.com/rrrene/html_sanitize_ex/commit/bec27fec4de99e40c68c4285a610e09e791a3eaf"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rrrene/html_sanitize_ex"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "html_sanitize_ex HTML5 scrubber keeps attacker-supplied `\u003cobject\u003e` elements, allowing untrusted content embedding"
}