CVE-2026-48747 in Symfony Mailomat Mailer
Symfony Mailomat Mailer lets the request choose the HMAC algorithm for webhook signature checks.
Quick answer
Symfony Mailomat Mailer should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- symfony/mailomat-mailer >=7.2.0 <7.4.13, >=8.0.0 <8.0.13
Fixed versions
- symfony/mailomat-mailer 7.4.13 or 8.0.13
How to fix it
Update Symfony Mailomat Mailer. The old package can let unsafe requests or URLs pass checks they should not pass.
- Update symfony/mailomat-mailer to symfony/mailomat-mailer 7.4.13 or 8.0.13 with Composer.
- Run the app test suite.
- Clear Symfony cache and redeploy.
- Check logs after release.
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Verify the fix
- Run composer show symfony/mailomat-mailer and confirm the fixed version is installed.
- Retest the affected route, webhook, login, or sanitizer path.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-48747?
Symfony Mailomat Mailer versions listed as affected should be reviewed: symfony/mailomat-mailer >=7.2.0 <7.4.13, >=8.0.0 <8.0.13.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.