CVE-2026-45071: Symfony/symfony :addXmlContent() Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-x6g4-fwcc-jj8w",
  "modified" : "2026-05-27T21:09:45Z",
  "published" : "2026-05-27T21:09:44Z",
  "aliases" : [ "CVE-2026-45071" ],
  "summary" : "Symfony has XXE (Local File Disclosure) in DomCrawler::addXmlContent() via validateOnParse = true",
  "details" : "### Description\n\n`symfony/dom-crawler` provides the `Crawler` class for navigating HTML/XML documents with CSS/XPath selectors; `symfony/browser-kit`'s `HttpBrowser` uses it to parse fetched pages.\n\n`Crawler::addXmlContent()` sets `DOMDocument::$validateOnParse = true` before calling `loadXML()`. Setting `validateOnParse` re-enables libxml's DTD subset processing, including external entity resolution, even though `LIBXML_NONET` is passed. `LIBXML_NONET` blocks **network** fetches but not `file://` entities. An attacker-supplied XML document with a `SYSTEM \"file:///etc/passwd\"` entity is therefore expanded.\n\n### Resolution\n\nThe `Crawler::addXmlContent` method does not set the `validateOnParse` flag anymore.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/eea5fd7488cbdc241da4ce242344b7d9a3ecdf3d) for branch 5.4.\n\n### Credits\n\nSymfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/dom-crawler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.4.52"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.4.52"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/dom-crawler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.4.40"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/dom-crawler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.4.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/dom-crawler"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.0.0"
      }, {
        "fixed" : "6.4.40"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.4.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
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      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/security/advisories/GHSA-x6g4-fwcc-jj8w"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/commit/eea5fd7488cbdc241da4ce242344b7d9a3ecdf3d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/dom-crawler/CVE-2026-45071.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45071.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/symfony/symfony"
  }, {
    "type" : "WEB",
    "url" : "https://symfony.com/cve-2026-45071"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-611" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-27T21:09:44Z",
    "nvd_published_at" : null
  }
}