{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "2.3.0"
              },
              {
                "fixed": "2.8.2"
              }
            ]
          },
          "events": [
            {
              "introduced": "32a49eb2b38fe5e5c417ab748a45d0beaab97955"
            },
            {
              "fixed": "59fb075d2101740c337c7216e3f32b36c204218b"
            }
          ],
          "repo": "https://github.com/thephpleague/commonmark",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-hh8v-hgvp-g3f5"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-185",
      "CWE-79",
      "CWE-918"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33347.json"
  },
  "details": "league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like youtube.com.evil passes the allowlist check when youtube.com is an allowed domain. This issue has been patched in version 2.8.2.",
  "id": "CVE-2026-33347",
  "modified": "2026-04-01T23:09:08.521181636Z",
  "published": "2026-03-24T19:26:23.872Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33347.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/thephpleague/commonmark/commit/59fb075d2101740c337c7216e3f32b36c204218b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thephpleague/commonmark/releases/tag/2.8.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-hh8v-hgvp-g3f5"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33347"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "league/commonmark has an embed extension allowed_domains bypass"
}