CVE-2026-47212: Symfony Twilio SMS Notifier Allows Unauthenticated Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-55rj-x2vc-4whq",
  "modified" : "2026-05-29T21:32:23Z",
  "published" : "2026-05-29T21:32:23Z",
  "aliases" : [ "CVE-2026-47212" ],
  "summary" : "Symfony: Twilio SMS Notifier allows unauthenticated webhook injection due to missing X-Twilio-Signature verification",
  "details" : "### Description\n\nThe Twilio SMS notifier bridge ships a webhook request parser used to authenticate and decode the status callbacks Twilio POSTs to an application's webhook endpoint. Its `doParse(Request $request, #[\\SensitiveParameter] string $secret)` method receives the configured webhook secret but never reads it; it decodes and returns the payload unconditionally, ignoring the `X-Twilio-Signature` HMAC header Twilio sends with each request.\n\nAs a result, an application that wires up the Twilio webhook endpoint accepts **any** POST to that URL, even when a signing secret is configured (the recommended setup). An attacker who knows the endpoint exists can submit forged status payloads, fake delivered / failed / undelivered events, leading to delivery-metrics fraud, downstream automation triggers, etc.\n\n### Resolution\n\n`TwilioRequestParser::doParse()` now requires and verifies the `X-Twilio-Signature` header (HMAC-SHA1 over the full request URL concatenated with the alphabetically-sorted POST parameters, base64-encoded, keyed with the Twilio account auth token) before further processing, using a constant-time comparison.\n\nWhen no secret is configured the behaviour is unchanged: signature verification remains opt-in, but it is now actually enforced once opted in.\n\nApplications behind a TLS-terminating reverse proxy must configure `framework.trusted_proxies` and `framework.trusted_headers` so that `Request::getUri()` returns the public URL Twilio signed.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/8545fb2af6c07dfb5ef0fc8d9bccf86db2c94356) for branch 6.4.\n\n### Credits\n\nSymfony would like to thank Himanshu Anand for reporting the issue and Nicolas Grekas for providing the fix.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/symfony"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.4.0"
      }, {
        "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"
      }, {
        "fixed" : "8.0.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/twilio-notifier"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "6.4.0"
      }, {
        "fixed" : "6.4.40"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/twilio-notifier"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.4.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "symfony/twilio-notifier"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.12"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/security/advisories/GHSA-55rj-x2vc-4whq"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/symfony/symfony/commit/8545fb2af6c07dfb5ef0fc8d9bccf86db2c94356"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-47212.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/twilio-notifier/CVE-2026-47212.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/symfony/symfony"
  }, {
    "type" : "WEB",
    "url" : "https://symfony.com/cve-2026-47212"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-306", "CWE-347" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-29T21:32:23Z",
    "nvd_published_at" : null
  }
}