GHSA-mh29-5h37-fv8m

Suggest an improvement
Source
https://github.com/advisories/GHSA-mh29-5h37-fv8m
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-mh29-5h37-fv8m/GHSA-mh29-5h37-fv8m.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-mh29-5h37-fv8m
Aliases
Downstream
Related
Published
2025-11-14T14:29:48Z
Modified
2025-11-17T15:20:43Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
Summary
js-yaml has prototype pollution in merge (<<)
Details

Impact

In js-yaml 4.1.0, 4.0.0, and 3.14.1 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.

Patches

Problem is patched in js-yaml 4.1.1 and 3.14.2.

Workarounds

You 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).

References

https://cheatsheetseries.owasp.org/cheatsheets/PrototypePollutionPreventionCheatSheet.html

Database specific 
{
    "severity": "MODERATE",
    "github_reviewed": true,
    "cwe_ids": [
        "CWE-1321"
    ],
    "nvd_published_at": "2025-11-13T16:15:57Z",
    "github_reviewed_at": "2025-11-14T14:29:48Z"
}
References

Affected packages

npm / js-yaml

Package

Name
js-yaml
View open source insights on deps.dev
Purl
pkg:npm/js-yaml

Affected ranges

Type
SEMVER
Events
Introduced
4.0.0
Fixed
4.1.1

npm / js-yaml

Package

Name
js-yaml
View open source insights on deps.dev
Purl
pkg:npm/js-yaml

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
3.14.2