GHSA-55rj-x2vc-4whq
Fix: symfony/symfony@8545fb2GHSA-55rj-x2vc-4whq is a Missing Authentication vulnerability in symfony/symfony. O3 Security confirms whether GHSA-55rj-x2vc-4whq is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony: Twilio SMS Notifier allows unauthenticated webhook injection due to missing X-Twilio-Signature verification
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-55rj-x2vc-4whq.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/twilio-notifier🐘symfony/twilio-notifier🐘symfony/twilio-notifierReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Description
The 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.
As 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.
Resolution
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.
When no secret is configured the behaviour is unchanged: signature verification remains opt-in, but it is now actually enforced once opted in.
Applications 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.
The patch for this issue is available here for branch 6.4.
Credits
Symfony would like to thank Himanshu Anand for reporting the issue and Nicolas Grekas for providing the fix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/symfony | ≥ 6.4.0&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/symfony | ≥ 7.0.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/symfony | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/twilio-notifier | ≥ 6.4.0&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/twilio-notifier | ≥ 7.0.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/twilio-notifier | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update symfony/symfony to 6.4.40 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-55rj-x2vc-4whq is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-55rj-x2vc-4whq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-55rj-x2vc-4whq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-55rj-x2vc-4whq in your dependencies?
O3 detects GHSA-55rj-x2vc-4whq across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.