EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
devalueReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
1. devalue.parse allows __proto__ to be set
A string passed to devalue.parse could represent an object with a __proto__ property, which would assign a prototype to an object while allowing properties to be overwritten:
class Vector {
constructor(x, y) {
this.x = x;
this.y = y;
}
get magnitude() {
return (this.x ** 2 + this.y ** 2) ** 0.5;
}
}
const payload = `[{"x":1,"y":2,"magnitude":3,"__proto__":4},3,4,"nope",["Vector",5],[6,7],8,9]`;
const vector = devalue.parse(payload, {
Vector: ([x, y]) => new Vector(x, y)
});
console.log("Is vector", vector instanceof Vector); // true
console.log(vector.x) // 3
console.log(vector.y) // 4
console.log(vector.magnitude); // "nope" instead of 5
2. devalue.parse allows array prototype methods to be assigned to object
In a payload constructed with devalue.stringify, values are represented as array indices, where the array contains the 'hydrated' values:
devalue.stringify({ message: 'hello' }); // [{"message":1},"hello"]
devalue.parse does not check that an index is numeric, which means that it could assign an array prototype method to a property instead:
const object = devalue.parse('[{"toString":"push"}]');
object.toString(); // 0
This could be used by a creative attacker to bypass server-side validation.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | devalue | all versions | 5.3.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for devalue. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update devalue to 5.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vj54-72f3-p5jv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-vj54-72f3-p5jv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-vj54-72f3-p5jv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-vj54-72f3-p5jv in your dependencies?
O3 detects GHSA-vj54-72f3-p5jv across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.