GHSA-mj3g-7xcc-x4vh

Source

https://github.com/advisories/GHSA-mj3g-7xcc-x4vh

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-mj3g-7xcc-x4vh/GHSA-mj3g-7xcc-x4vh.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-mj3g-7xcc-x4vh

Aliases

CVE-2026-54737

Published

2026-07-31T17:49:08Z

Modified

2026-07-31T18:11:48Z

Severity

7.3 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L CVSS Calculator

Summary

@phun-ky/defaults-deep Has a Prototype Pollution issue via Unsafe Recursive Property Merging

Details

Impact

A prototype pollution vulnerability exists in @phun-ky/defaults-deep prior to version 2.0.5.

The library recursively merged user-supplied objects without filtering unsafe property names such as __proto__, constructor, and prototype. An attacker able to supply crafted input could cause properties to be written to Object.prototype, resulting in prototype pollution affecting all objects within the running process.

Applications that pass untrusted input to defaultsDeep() may be impacted. Depending on how the application uses merged objects, this could lead to unexpected behavior, logic bypasses, denial of service, or other security issues.

Patches

This issue has been fixed in version 2.0.5.

Users should upgrade to version 2.0.5 or later.

The fix prevents unsafe prototype-related keys (__proto__, constructor, and prototype) from being processed during recursive merge operations and includes regression tests covering known prototype pollution vectors.

Workarounds

Users unable to upgrade should ensure that untrusted input is sanitized before being passed to defaultsDeep().

At a minimum, applications should reject or remove the following property names from all levels of user-controlled objects:

__proto__
constructor
prototype

Upgrading to a patched version remains the recommended mitigation.

Database specific

{
    "cwe_ids":  [
        "CWE-1321"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-07-31T17:49:08Z",
    "nvd_published_at":  null,
    "severity":  "HIGH"
}

References

Affected packages

npm / @phun-ky/defaults-deep

Package

Name: @phun-ky/defaults-deep; View open source insights on deps.dev
Purl: pkg:npm/%40phun-ky/defaults-deep

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

2.0.5

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-mj3g-7xcc-x4vh/GHSA-mj3g-7xcc-x4vh.json"