What is CVE-2019-18413?

CVE-2019-18413 is a critical-severity cross-site scripting (XSS) vulnerability in class-validator (npm), affecting versions < 0.14.0. It is fixed in 0.14.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.

How severe is CVE-2019-18413?

CVE-2019-18413 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of class-validator are affected by CVE-2019-18413?

class-validator (npm) versions < 0.14.0 is affected.

Is there a fix for CVE-2019-18413?

Yes. CVE-2019-18413 is fixed in 0.14.0. Upgrade to this version or later.

Is CVE-2019-18413 exploitable, and should I be worried?

Whether CVE-2019-18413 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.

What actually determines whether CVE-2019-18413 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.

CVE-2019-18413 in class-validator

Q: How severe is CVE-2019-18413?

CVE-2019-18413 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of class-validator are affected by CVE-2019-18413?

class-validator (npm) versions < 0.14.0 is affected.

Q: Is there a fix for CVE-2019-18413?

Yes. CVE-2019-18413 is fixed in 0.14.0. Upgrade to this version or later.

Q: Is CVE-2019-18413 exploitable, and should I be worried?

Whether CVE-2019-18413 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.

Q: What actually determines whether CVE-2019-18413 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.

Q: How do I fix CVE-2019-18413?

Upgrade class-validator to 0.14.0 or later.

Summary

SQL Injection and Cross-site Scripting in class-validator

In TypeStack class-validator, validate() input validation can be bypassed because certain internal attributes can be overwritten via a conflicting name. Even though there is an optional forbidUnknownValues parameter that can be used to reduce the risk of this bypass, this option is not documented and thus most developers configure input validation in the vulnerable default manner. With this vulnerability, attackers can launch SQL Injection or XSS attacks by injecting arbitrary malicious input.

The default settings for forbidUnknownValues has been changed to true in 0.14.0.

NOTE: a software maintainer agrees with the "is not documented" finding but suggests that much of the responsibility for the risk lies in a different product.

Impact

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2019-18413 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.14.0); upgrading removes the vulnerable code path.

Affected versions

class-validator (< 0.14.0)

Security releases

class-validator → 0.14.0 (npm)

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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Remediation advice

Upgrade class-validator to 0.14.0 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2019-18413? CVE-2019-18413 is a critical-severity cross-site scripting (XSS) vulnerability in class-validator (npm), affecting versions < 0.14.0. It is fixed in 0.14.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
How severe is CVE-2019-18413? CVE-2019-18413 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of class-validator are affected by CVE-2019-18413? class-validator (npm) versions < 0.14.0 is affected.
Is there a fix for CVE-2019-18413? Yes. CVE-2019-18413 is fixed in 0.14.0. Upgrade to this version or later.
Is CVE-2019-18413 exploitable, and should I be worried? Whether CVE-2019-18413 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 CVE-2019-18413 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 CVE-2019-18413? Upgrade class-validator to 0.14.0 or later.