CVE-2026-45068: Symfony Mailer argument injection in SendmailTransport

CVE-2026-45068 · Severity: medium · CVSS 4 · Published 2026-07-14

Symfony is a popular PHP framework used to build web applications. A security flaw in its email-sending component could allow an attacker to manipulate the underlying mail server by providing a specially crafted email address. This could lead to unauthorized actions on the server, such as modifying how emails are sent or potentially accessing sensitive system information.

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

Quick answers

Is CVE-2026-45068 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45068 being exploited in the wild.
How severe is CVE-2026-45068?
Medium severity, with a CVSS score of 4, published 14 July 2026.
Which products and versions are affected?
symfony/mailer (Packagist) ECOSYSTEM:introduced=0,fixed=5.4.52; symfony/symfony (Packagist) ECOSYSTEM:introduced=0,fixed=5.4.52; Symfony Mailer < 5.4.52, >= 6.0.0-BETA1 < 6.4.40, >= 7.0.0-BETA1 < 7.4.12, >= 8.0.0-BETA1 < 8.0.12, < 5.4.52, >= 6.0.0, < 6.4.40, >= 7.0.0, < 7.4.12, >= 8.0.0, < 8.0.12.
Is there a fix for CVE-2026-45068?
Yes. symfony/mailer (Packagist): upgrade to 5.4.52 or later; symfony/symfony (Packagist): upgrade to 5.4.52 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45068 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-45068?
Check whether you run symfony/mailer (Packagist), symfony/symfony (Packagist) or Symfony Mailer 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/mailer (Packagist): upgrade to 5.4.52 or later
    composer require symfony/mailer:^5.4.52
  • symfony/symfony (Packagist): upgrade to 5.4.52 or later
    composer require symfony/symfony:^5.4.52

Technical details

An argument injection vulnerability exists in Symfony's Mailer component, specifically within the SendmailTransport class when used in '-t' mode. The component appended recipient addresses to the sendmail command line without the '--' end-of-options separator. This allows an attacker who can control a recipient email address to inject arbitrary sendmail command-line flags by providing an address starting with a dash (e.g., '-O'). This is classified as CWE-88. The issue is resolved in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12 by adding the separator and rejecting addresses starting with a dash.

Affected products

  • symfony symfony < 5.4.52, >= 6.0.0-BETA1 < 6.4.40, >= 7.0.0-BETA1 < 7.4.12, >= 8.0.0-BETA1 < 8.0.12
  • symfony mailer < 5.4.52, >= 6.0.0-BETA1 < 6.4.40, >= 7.0.0-BETA1 < 7.4.12, >= 8.0.0-BETA1 < 8.0.12

Identifiers

  • CVE-2026-45068
  • GHSA-xx3c-qf5g-hc39

Timeline

  • 2026-07-14: advisory
  • 2026-05-20: patched

References

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