{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.8.3"
              },
              {
                "fixed": "0.13.2"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "a1e2980f3fba07358d0d3d1a76ae23c9b5639f3f"
            },
            {
              "fixed": "c05684d9e78fc879d71ad39f2f5827b124cb5881"
            },
            {
              "fixed": "2817147f5b87ce7186aa604c9ee72499485b8f2f"
            }
          ],
          "repo": "https://github.com/leandrocp/mdex",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-4383-7xfp-gpph"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54889.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "9852db2456fdc9d856eb636603a7f608e22e3793"
          },
          {
            "fixed": "2817147f5b87ce7186aa604c9ee72499485b8f2f"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in leandrocp mdex allows cross-site scripting via unsanitized URL schemes in Quill Delta output.\n\n'Elixir.MDEx':to_delta/2 converts Markdown into a Quill Delta. 'Elixir.MDEx.DeltaConverter':default_convert_node/3 in lib/mdex/delta_converter.ex copies the URL of a link, wikilink, or image node directly from the parsed Markdown into the Delta \"link\" or \"image\" attribute without applying a scheme allowlist or any normalization.\n\nAn attacker who controls the Markdown text can supply a javascript: URL (for example [click](javascript:alert(document.cookie))) that survives verbatim into the Delta attribute. When the Delta is rendered to HTML by a downstream renderer (such as quill-delta-to-html or the Quill client), the attribute becomes an \u003ca href\u003e or \u003cimg src\u003e, and the javascript: scheme executes in the browser of anyone who views the rendered content. The link and wikilink cases are the strongest vectors because javascript: in an href executes on click; the image case is lower impact because javascript: in \u003cimg src\u003e generally does not execute in modern browsers.\n\nThis issue affects mdex: from 0.8.3 before 0.13.2.",
  "id": "CVE-2026-54889",
  "modified": "2026-07-15T01:49:07.930746543Z",
  "published": "2026-06-29T19:10:49.841Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-54889.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-54889"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54889.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/leandrocp/mdex/security/advisories/GHSA-4383-7xfp-gpph"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54889"
    },
    {
      "type": "FIX",
      "url": "https://github.com/leandrocp/mdex/commit/2817147f5b87ce7186aa604c9ee72499485b8f2f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/leandrocp/mdex"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Unsanitized URL schemes in MDEx Quill Delta output allow javascript: injection (XSS)"
}