How severe is GHSA-64hg-93w9-fc35?

No CVSS score has been assigned to GHSA-64hg-93w9-fc35 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-64hg-93w9-fc35?

GHSA-64hg-93w9-fc35 affects the following packages: symfony/lox24-notifier (Packagist), symfony/lox24-notifier (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/mailjet-mailer (Packagist), symfony/mailjet-mailer (Packagist), symfony/mailjet-mailer (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-64hg-93w9-fc35?

Update symfony/lox24-notifier to 7.4.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-64hg-93w9-fc35 is resolved across your whole dependency graph.

How do I detect GHSA-64hg-93w9-fc35 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/lox24-notifier, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-64hg-93w9-fc35 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-64hg-93w9-fc35 actively exploited in the wild?

No public exploit code has been indexed for GHSA-64hg-93w9-fc35 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-64hg-93w9-fc35?

GHSA-64hg-93w9-fc35 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 37th 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-64hg-93w9-fc35?

GHSA-64hg-93w9-fc35 is classified as Improper Authentication (CWE-287), Missing Authentication (CWE-306). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-64hg-93w9-fc35 published, and has it been updated?

GHSA-64hg-93w9-fc35 was published on May 28, 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's Mailjet Mailer Webhook Parser Never Verifies the Configured Secret — Unauthenticated Webhook Event InjectionGHSA-64hg-93w9-fc35

Fix: symfony/symfony@4aaa45d

GHSA-64hg-93w9-fc35 is a Improper Authentication vulnerability in symfony/lox24-notifier. A fix is available for symfony/lox24-notifier — see the affected versions and patch details below.

Also known asCVE-2026-45754

Published

May 28, 2026

Updated

Sep 10, 2026

Affected

8 pkgs

Patched

8 / 8

Exploits

None indexed

Exploitation data as of Oct 9, 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-64hg-93w9-fc35.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs37th percentile — riskier than 37% of all scored CVEsHighest risk

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

Real-World Exposure

8 pkgs affected

🐘symfony/lox24-notifier🐘symfony/lox24-notifier🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/mailjet-mailer🐘symfony/mailjet-mailer🐘symfony/mailjet-mailer

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 Mailjet mailer bridge and the LOX24 SMS notifier bridge both ship webhook request parsers used to authenticate and decode the event callbacks each provider POSTs to an application's webhook endpoint. Their doParse(Request $request, #[\SensitiveParameter] string $secret) methods receive the configured webhook secret but never read it; they convert and return the payload unconditionally.

As a result, an application that wires up either webhook endpoint accepts any POST to that URL, even when a webhook secret is configured (the recommended setup). An attacker who knows the endpoint exists can submit forged event payloads, fake bounce / blocked / spam / open / click / delivery events, leading to suppression-list corruption, delivery-metrics fraud, etc.

Resolution

MailjetRequestParser::doParse() now rejects the request unless it carries the expected HTTP Basic credentials, Mailjet's webhook authentication mechanism, using a constant-time comparison. The configured webhook secret is matched against the credentials embedded in the Mailjet webhook URL as user:password (use :password when the URL has no username).

Lox24RequestParser::doParse() now rejects the request unless it carries an X-LOX24-Token HTTP header whose value matches the configured secret, using a constant-time comparison. The same token must be configured in the LOX24 dashboard under the callback settings.

When no secret is configured the behaviour is unchanged: webhook authentication remains opt-in, but it is now actually enforced once opted in.

The Mailjet patch is available here for branch 6.4.

The LOX24 patch is available here for branch 7.4 (the LOX24 bridge was introduced in 7.1 and is not present in 6.4).

Credits

Symfony would like to thank Himanshu Anand for reporting the issue, and Alexandre Daubois and Nicolas Grekas for providing the fixes.

Affected Packages

8 total 8 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symfony/lox24-notifier`	≥ 7.1.0&&< 7.4.12	7.4.12`composer require symfony/lox24-notifier:^7.4.12`
🐘Packagist	`symfony/lox24-notifier`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/lox24-notifier:^8.0.12`
🐘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/mailjet-mailer`	≥ 6.4.0&&< 6.4.40	6.4.40`composer require symfony/mailjet-mailer:^6.4.40`

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/lox24-notifier, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/lox24-notifier to 7.4.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-64hg-93w9-fc35 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 Mailjet mailer bridge and the LOX24 SMS notifier bridge both ship webhook request parsers used to authenticate and decode the event callbacks each provider POSTs to an application's webhook endpoint. Their `doParse(Request $request, #[\SensitiveParameter] string $secret)` methods receive the configured webhook secret but never read it; they convert and return the payload unconditionally. As a result, an application that wires up either webhook endpoint accepts **any** POST to that URL, even when a webhook secret is configured (the recommended setup). An attacker who knows

O3 Security · Impact-Aware SCA

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Symfony's Mailjet Mailer Webhook Parser Never Verifies the Configured Secret — Unauthenticated Webhook Event InjectionGHSA-64hg-93w9-fc35

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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