How severe is GHSA-55rj-x2vc-4whq?

No CVSS score has been assigned to GHSA-55rj-x2vc-4whq yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-55rj-x2vc-4whq?

GHSA-55rj-x2vc-4whq affects the following packages: symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/twilio-notifier (Packagist), symfony/twilio-notifier (Packagist), symfony/twilio-notifier (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-55rj-x2vc-4whq?

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.

How do I detect GHSA-55rj-x2vc-4whq in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-55rj-x2vc-4whq if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is GHSA-55rj-x2vc-4whq actively exploited in the wild?

No public exploit code has been indexed for GHSA-55rj-x2vc-4whq yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-55rj-x2vc-4whq?

GHSA-55rj-x2vc-4whq has an EPSS (Exploit Prediction Scoring System) score of 1.5%, placing it in the 74th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-55rj-x2vc-4whq?

GHSA-55rj-x2vc-4whq is classified as Missing Authentication (CWE-306), CWE-347 (CWE-347). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-55rj-x2vc-4whq published, and has it been updated?

GHSA-55rj-x2vc-4whq was published on May 29, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

Symfony: Twilio SMS Notifier allows unauthenticated webhook injection due to missing X-Twilio-Signature verificationGHSA-55rj-x2vc-4whq

Fix: symfony/symfony@8545fb2

GHSA-55rj-x2vc-4whq is a Missing Authentication vulnerability in symfony/symfony. A fix is available for symfony/symfony — see the affected versions and patch details below.

Also known asCVE-2026-47212

Published

May 29, 2026

Updated

Sep 10, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

1.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs74th percentile — riskier than 74% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

6 pkgs affected

🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/twilio-notifier🐘symfony/twilio-notifier🐘symfony/twilio-notifier

Real-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

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

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symfony/symfony`	≥ 6.4.0&&< 6.4.40	6.4.40`composer require symfony/symfony:^6.4.40`
🐘Packagist	`symfony/symfony`	≥ 7.0.0&&< 7.4.12	7.4.12`composer require symfony/symfony:^7.4.12`
🐘Packagist	`symfony/symfony`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/symfony:^8.0.12`
🐘Packagist	`symfony/twilio-notifier`	≥ 6.4.0&&< 6.4.40	6.4.40`composer require symfony/twilio-notifier:^6.4.40`
🐘Packagist	`symfony/twilio-notifier`	≥ 7.0.0&&< 7.4.12	7.4.12`composer require symfony/twilio-notifier:^7.4.12`
🐘Packagist	`symfony/twilio-notifier`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/twilio-notifier:^8.0.12`

Affected Products

1 product · 3 configurations

Application

symfonysensiolabs

≥ 8.0.0 && < 8.0.12

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/symfony, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### 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

O3 Security · Impact-Aware SCA

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Symfony: Twilio SMS Notifier allows unauthenticated webhook injection due to missing X-Twilio-Signature verificationGHSA-55rj-x2vc-4whq

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Description

Resolution

Credits

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

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