Summary
In some circumstances, devalue.parse and devalue.unflatten could emit objects with __proto__ own properties. This in and of itself is not a security vulnerability (and is possible with, for example, JSON.parse as well), but it can result in prototype injection if downstream code handles it incorrectly:
const result = devalue.parse(/* input creating an object with a __proto__ property */);
const target = {};
Object.assign(target, result); // target's prototype is now polluted
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.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-MWV9-GP5H-FRR4? GHSA-MWV9-GP5H-FRR4 is a low-severity security vulnerability in devalue (npm), affecting versions >= 4.0.0, < 5.6.4. It is fixed in 5.6.4.
- Which versions of devalue are affected by GHSA-MWV9-GP5H-FRR4? devalue (npm) versions >= 4.0.0, < 5.6.4 is affected.
- Is there a fix for GHSA-MWV9-GP5H-FRR4? Yes. GHSA-MWV9-GP5H-FRR4 is fixed in 5.6.4. Upgrade to this version or later.
- Is GHSA-MWV9-GP5H-FRR4 exploitable, and should I be worried? Whether GHSA-MWV9-GP5H-FRR4 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-MWV9-GP5H-FRR4 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-MWV9-GP5H-FRR4? Upgrade
devalueto 5.6.4 or later.