CVE-2026-45754: Symfony missing webhook secret verification in Mailjet and LOX24 bridges

CVE-2026-45754 · Severity: medium · CVSS 4 · Published 2026-07-14

A vulnerability in the Symfony web framework allows attackers to send fake notifications or email status updates to applications using Mailjet or LOX24. The software failed to check security credentials for incoming webhooks, meaning an unauthorized person could trigger actions in your system by pretending to be a trusted service. This could lead to incorrect data being processed or automated workflows being triggered by fraudulent information.

Technologies: symfony/symfony (Packagist). Vendors: Packagist, Symfony.

Quick answers

Is CVE-2026-45754 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45754 being exploited in the wild.
How severe is CVE-2026-45754?
Medium severity, with a CVSS score of 4, published 14 July 2026.
Which products and versions are affected?
symfony/lox24-notifier (Packagist) ECOSYSTEM:introduced=7.1.0,fixed=7.4.12; symfony/mailjet-mailer (Packagist) ECOSYSTEM:introduced=6.4.0,fixed=6.4.40; symfony/symfony (Packagist) ECOSYSTEM:introduced=6.4.0,fixed=6.4.40.
Is there a fix for CVE-2026-45754?
Yes. symfony/lox24-notifier (Packagist): upgrade to 7.4.12 or later; symfony/mailjet-mailer (Packagist): upgrade to 6.4.40 or later; symfony/symfony (Packagist): upgrade to 6.4.40 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45754 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-45754?
Check whether you run symfony/lox24-notifier (Packagist), symfony/mailjet-mailer (Packagist), symfony/symfony (Packagist) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • symfony/lox24-notifier (Packagist): upgrade to 7.4.12 or later
    composer require symfony/lox24-notifier:^7.4.12
  • symfony/mailjet-mailer (Packagist): upgrade to 6.4.40 or later
    composer require symfony/mailjet-mailer:^6.4.40
  • symfony/symfony (Packagist): upgrade to 6.4.40 or later
    composer require symfony/symfony:^6.4.40

Technical details

A missing authentication check (CWE-306) exists in Symfony's Mailjet and LOX24 bridge components. The webhook parsers for these services received configured secrets but failed to perform verification against incoming POST requests. An unauthenticated remote attacker can exploit this by sending forged HTTP POST payloads to the webhook endpoint, potentially triggering application logic associated with email delivery events or notification statuses. The issue is resolved by enforcing Basic credential verification for Mailjet and token verification for LOX24 in versions 6.4.40, 7.4.12, and 8.0.12.

Affected products

  • Symfony symfony/symfony >= 6.4.0, < 6.4.40; >= 7.0.0-BETA1, < 7.4.12; >= 8.0.0-BETA1, < 8.0.12
  • Symfony lox24-notifier >= 7.1.0-BETA1, < 7.4.12; >= 8.0.0-BETA1, < 8.0.12
  • Symfony mailjet-mailer >= 6.4.0, < 6.4.40; >= 7.0.0-BETA1, < 7.4.12; >= 8.0.0-BETA1, < 8.0.12

Identifiers

  • CVE-2026-45754
  • GHSA-64hg-93w9-fc35

Timeline

  • 2026-07-14: disclosed
  • 2026-07-14: advisory
  • 2026-05-20: patched: Release date of fixed versions 6.4.40, 7.4.12, and 8.0.12

References

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