{"id":"CVE-2026-47212","aliases":["GHSA-55rj-x2vc-4whq"],"url":"https://o3.security/vulnerability/CVE-2026-47212","summary":"Symfony: Twilio Notifier Webhook Parser Never Verifies the X-Twilio-Signature HMAC: Unauthenticated Webhook Event Injection","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.","published":"2026-07-14T19:00:30.703Z","modified":"2026-08-12T03:51:15.102972441Z","cvss":null,"epss":{"score":0.01506,"percentile":0.7312,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"6.4.40"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"7.4.12"},{"ecosystem":"Packagist","name":"symfony/symfony","fixedVersion":"8.0.12"},{"ecosystem":"Packagist","name":"symfony/twilio-notifier","fixedVersion":"6.4.40"},{"ecosystem":"Packagist","name":"symfony/twilio-notifier","fixedVersion":"7.4.12"},{"ecosystem":"Packagist","name":"symfony/twilio-notifier","fixedVersion":"8.0.12"}],"fix":{"url":"https://github.com/symfony/symfony/commit/8545fb2af6c07dfb5ef0fc8d9bccf86db2c94356","label":"symfony/symfony@8545fb2"},"references":[{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v6.4.40"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v7.4.12"},{"type":"WEB","url":"https://github.com/symfony/symfony/releases/tag/v8.0.12"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47212.json"},{"type":"ADVISORY","url":"https://github.com/symfony/symfony/security/advisories/GHSA-55rj-x2vc-4whq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47212"},{"type":"FIX","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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:15.102972441Z"}}