What’s Vulnerable › Vulnerabilities

CVE-2026-45754: Symfony: Mailjet Mailer Webhook Parser Never Verifies the Configured Secret — Unauthenticated Webhook Event Injection

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-14 · updated 2026-07-21
• Weakness: CWE-287

Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 6.4.40, 7.4.12, and 8.0.12, the Mailjet mailer bridge and LOX24 notifier bridge webhook parsers received configured webhook secrets but did not verify them, allowing unauthenticated POST requests to inject forged Mailjet and LOX24 event payloads. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

Affected products

• symfony: from 6.4.0 before 6.4.40; from 7.0.0 before 7.4.12; from 8.0.0 before 8.0.12 — fixed in 6.4.40, 7.4.12, 8.0.12

How to fix

Upgrade to a fixed version: symfony 6.4.40, 7.4.12, 8.0.12. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/symfony/commit/3e52bf5ab733ee32e35eeeeb2631d859c941838e
• https://github.com/symfony/symfony/commit/4aaa45dd054f73445f1ab254968b7e60b546cc77
• https://github.com/symfony/symfony/releases/tag/v6.4.40
• https://github.com/symfony/symfony/releases/tag/v7.4.12
• https://github.com/symfony/symfony/releases/tag/v8.0.12
• https://github.com/symfony/symfony/security/advisories/GHSA-64hg-93w9-fc35

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