Advisories for Npm/Devalue package

2026

Sveltejs devalue's `devalue.parse` and `devalue.unflatten` emit objects with `__proto__` own properties

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

devalue affected by CPU and memory amplification from sparse arrays

Under certain circumstances, serializing sparse arrays using uneval or stringify could cause CPU and/or memory exhaustion. When this occurs on the server, it results in a DoS. This is extremely difficult to take advantage of in practice, as an attacker would have to manage to create a sparse array on the server — which is impossible in every mainstream wire format — and then that sparse array would have to …

devalue vulnerable to denial of service due to memory/CPU exhaustion in devalue.parse

Certain inputs can cause devalue.parse to consume excessive CPU time and/or memory, potentially leading to denial of service in systems that parse input from untrusted sources. This affects applications using devalue.parse on externally-supplied data. The root cause is the ArrayBuffer hydration expecting base64 encoded strings as input, but not checking the assumption before decoding the input.

Devalue is vulnerable to denial of service due to memory exhaustion in devalue.parse

Certain inputs can cause devalue.parse to consume excessive CPU time and/or memory, potentially leading to denial of service in systems that parse input from untrusted sources. This affects applications using devalue.parse on externally-supplied data. The root cause is the typed array hydration expecting an ArrayBuffer as input, but not checking the assumption before creating the typed array.

2025

devalue prototype pollution vulnerability

  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, …