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).
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 14 Nov 2025 09:30:00 +0000

Type Values Removed Values Added
First Time appeared Js-yaml
Js-yaml js-yaml
Vendors & Products Js-yaml
Js-yaml js-yaml

Thu, 13 Nov 2025 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 13 Nov 2025 15:45:00 +0000

Type Values Removed Values Added
Description 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).
Title js-yaml has prototype pollution in merge (<<)
Weaknesses CWE-1321
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-11-13T16:18:39.270Z

Reserved: 2025-11-10T14:07:42.922Z

Link: CVE-2025-64718

cve-icon Vulnrichment

Updated: 2025-11-13T16:18:34.960Z

cve-icon NVD

Status : Received

Published: 2025-11-13T16:15:57.153

Modified: 2025-11-13T16:15:57.153

Link: CVE-2025-64718

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2025-11-14T09:28:09Z