js-yaml is a JavaScript YAML parser and dumper. In js-yaml 4.1.0 and below, 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. 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).
| Package (Ecosystem) | Introduced | Fixed | Limit |
|---|---|---|---|
| js-yaml(npm) | 4.0.0 | 4.1.1 | N/A |
| js-yaml(npm) | 0 | 3.14.2 | N/A |
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