CVE-2026-45068 in Symfony Mailer
Symfony Mailer can pass a dash-prefixed recipient address to SendmailTransport in an unsafe way, which can let an attacker inject sendmail arguments.
Quick answer
Symfony 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/mailer <5.4.52, >=6.0.0 <6.4.40, >=7.0.0 <7.4.12, >=8.0.0 <8.0.12
Fixed versions
- symfony/mailer 5.4.52, 6.4.40, 7.4.12, or 8.0.12
How to fix it
Update Symfony Mailer. The old version can let unsafe input change how the app works.
- Update symfony/mailer to symfony/mailer 5.4.52, 6.4.40, 7.4.12, or 8.0.12 with Composer.
- Run the app test suite.
- Clear Symfony cache and redeploy.
- Check logs for errors after release.
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Verify the fix
- Run composer show symfony/mailer and confirm the fixed version is installed.
- Retest the route, mailer, or sanitizer path that used the affected package.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-45068?
Symfony Mailer versions listed as affected should be reviewed: symfony/mailer <5.4.52, >=6.0.0 <6.4.40, >=7.0.0 <7.4.12, >=8.0.0 <8.0.12.
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.