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PatchSiren cyber security CVE debrief

CVE-2026-45754 Sensiolabs CVE debrief

The Symfony framework, widely used for web and console applications, had a vulnerability in its Mailjet mailer bridge and LOX24 notifier bridge. Prior to versions 6.4.40, 7.4.12, and 8.0.12, these bridges did not verify configured webhook secrets. This oversight allowed unauthenticated POST requests to inject forged Mailjet and LOX24 event payloads. The issue has been addressed in Symfony versions 6.4.40, 7.4.12, and 8.0.12. Developers and administrators using Symfony, especially those integrating Mailjet and LOX24 services, should verify their installations and update to the patched versions to prevent potential abuse.

Vendor
Sensiolabs
Product
Symfony
CVSS
MEDIUM 6.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-21
Advisory published
2026-07-14
Advisory updated
2026-07-21

Who should care

Developers and administrators using Symfony, especially those integrating Mailjet and LOX24 services, should verify their installations and update to the patched versions to prevent potential abuse. This includes reviewing webhook secrets configuration, monitoring for suspicious requests, and implementing additional authentication mechanisms for webhook endpoints if possible.

Technical summary

Symfony's Mailjet mailer bridge and LOX24 notifier bridge did not verify webhook secrets, allowing unauthenticated POST requests to inject forged event payloads. This issue, fixed in Symfony versions 6.4.40, 7.4.12, and 8.0.12, could lead to security risks if exploited. The vulnerability affects Symfony framework users who integrate Mailjet and LOX24 services. Developers and administrators should review their installations and update to the patched versions.

Defensive priority

Medium priority due to the potential for injecting forged event payloads.

Recommended defensive actions

  • Update Symfony to version 6.4.40, 7.4.12, or 8.0.12
  • Verify webhook secrets configuration for Mailjet and LOX24 bridges
  • Monitor for suspicious POST requests to Mailjet and LOX24 webhook endpoints
  • Implement additional authentication mechanisms for webhook endpoints if possible
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-07-14T19:17:07.777Z and last modified on 2026-07-16T03:12:34.113Z. The NVD entry is currently Analyzed. Evidence from the CVE record and NVD entry indicates that Symfony's Mailjet mailer bridge and LOX24 notifier bridge did not verify webhook secrets, allowing unauthenticated POST requests to inject forged event payloads. This issue is fixed in Symfony versions 6.4.40, 7.4.12, and 8.0.12. Defenders should verify their installations and update to the patched versions to prevent potential abuse.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45754 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45754

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-45754 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45754

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.