CVE-2025-64718
Medium
Description
js-yaml is a JavaScript YAML parser and dumper. In js-yaml before 4.1.1 and 3.14.2, it's possible for an attacker to modify the prototype of the result of a parsed yaml document via prototype pollution (`__proto__`). All users who parse untrusted yaml documents may be impacted. The problem is patched in js-yaml 4.1.1 and 3.14.2. Users can protect against this kind of attack on the server by using `node --disable-proto=delete` or `deno` (in Deno, pollution protection is on by default).
SeverityMedium
CVSS5.3
Exploit probability—
ProductNodeca Js-yaml
PublishedNov 13, 2025
First seenNov 13, 2025
Weakness typeCWE-1321Prototype pollution
How to fix
Update
- nodeca js-yaml3.14.2, 4.1.1 or later
- js-yaml4.1.1, 3.14.2 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| nodeca js-yaml | v < 3.14.2, 4.0.0 ≤ v < 4.1.1 | 3.14.2, 4.1.1 |
| js-yamlnpm | 4.0.0 ≤ v < 4.1.1, v < 3.14.2 | 4.1.1, 3.14.2 |
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