Summary
Swiftmailer Sendmail transport arbitrary shell execution
Prior to 5.2.1, the sendmail transport (Swift_Transport_SendmailTransport) was vulnerable to an arbitrary shell execution if the "From" header came from a non-trusted source and no "Return-Path" is configured. This has been fixed in 5.2.1. If you are using sendmail as a transport, you are encouraged to upgrade as soon as possible.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-4QPJ-GXXG-JQG4? GHSA-4QPJ-GXXG-JQG4 is a critical-severity security vulnerability in swiftmailer/swiftmailer (composer), affecting versions >= 4.0.0, < 5.2.1. It is fixed in 5.2.1.
- Which versions of swiftmailer/swiftmailer are affected by GHSA-4QPJ-GXXG-JQG4? swiftmailer/swiftmailer (composer) versions >= 4.0.0, < 5.2.1 is affected.
- Is there a fix for GHSA-4QPJ-GXXG-JQG4? Yes. GHSA-4QPJ-GXXG-JQG4 is fixed in 5.2.1. Upgrade to this version or later.
- Is GHSA-4QPJ-GXXG-JQG4 exploitable, and should I be worried? Whether GHSA-4QPJ-GXXG-JQG4 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-4QPJ-GXXG-JQG4 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-4QPJ-GXXG-JQG4? Upgrade
swiftmailer/swiftmailerto 5.2.1 or later.