GHSA-4q55-j62x-fr9h

Source

https://github.com/advisories/GHSA-4q55-j62x-fr9h

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-4q55-j62x-fr9h/GHSA-4q55-j62x-fr9h.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-4q55-j62x-fr9h

Downstream

CLSA-2026-1790888237

Published

2026-10-01T15:13:23Z

Modified

2026-10-01T15:30:05Z

Severity

6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N CVSS Calculator

Summary

devalue: Malformed null-prototype object keys bypass __proto__ rejection via property-key coercion

Details

This is another instance of https://github.com/sveltejs/devalue/security/advisories/GHSA-mwv9-gp5h-frr4, where some payloads could cause parse to create objects with a __proto__ own property. This on its own is not enough to cause prototype pollution, and indeed this is actually how JSON.parse works, but we decided to be a little more defensive here and not allow the creation of objects with __proto__ own-properties. It is very unlikely for this to cause any issues.

Database specific

{
    "cwe_ids":  [
        "CWE-1321"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-01T15:13:23Z",
    "nvd_published_at":  null,
    "severity":  "MODERATE"
}

References

Affected packages

npm / devalue

Package

Name: devalue; View open source insights on deps.dev
Purl: pkg:npm/devalue

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

5.9.3

Database specific

last_known_affected_version_range

"<= 5.9.2"

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-4q55-j62x-fr9h/GHSA-4q55-j62x-fr9h.json"