GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 12.0.1, the GraphQL Tools utils package's mergeDeep function follows inherited properties while recursively merging source objects and does not exclude __proto__, constructor, or prototype keys. An unauthenticated GraphQL client can alias fields to those names so responses from two subgraphs collide during ordinary supergraph result merging, causing mergeDeep to traverse Object and Function prototypes and overwrite Function.prototype.call with a subgraph-supplied value. This breaks subsequent requests in the process until restart. This issue is fixed in version 12.0.1.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-7mx3-vvmw-hjmv GraphQL Tools has prototype pollution in well-established utility function `mergeDeep`
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 06 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
First Time appeared Ardatan
Ardatan graphql-tools
Vendors & Products Ardatan
Ardatan graphql-tools

Mon, 05 Oct 2026 23:00:00 +0000

Type Values Removed Values Added
Description GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 12.0.1, the GraphQL Tools utils package's mergeDeep function follows inherited properties while recursively merging source objects and does not exclude __proto__, constructor, or prototype keys. An unauthenticated GraphQL client can alias fields to those names so responses from two subgraphs collide during ordinary supergraph result merging, causing mergeDeep to traverse Object and Function prototypes and overwrite Function.prototype.call with a subgraph-supplied value. This breaks subsequent requests in the process until restart. This issue is fixed in version 12.0.1.
Title GraphQL Tools has prototype pollution in well-established utility function `mergeDeep`
Weaknesses CWE-1321
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-05T22:56:43.779Z

Reserved: 2026-10-02T14:38:43.244Z

Link: CVE-2026-104852

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-05T23:17:00.213

Modified: 2026-10-05T23:17:00.213

Link: CVE-2026-104852

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-06T00:30:18Z

Weaknesses