CVE-2025-64718: Nodeca Js-Yaml

Medium severity, CVSS 5.3. EPSS: 0.4% chance of exploitation in the next 30 days.

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).

Affected products

• Nodeca Js-Yaml: before 3.14.2 (fixed in 3.14.2); from 4.0.0, before 4.1.1 (fixed in 4.1.1)

Published 2025-11-13. Last modified 2026-10-07.