---
id: CVE-2026-104852
title: >-
  GraphQL Tools provides utilities for building, stitching, and mocking GraphQL
  schemas
summary: >-
  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
  n…
severity: high
cvss: 8.2
cvssVector: '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'
cwe:
  - CWE-1321
vendor: graphql-tools
product: '@graphql-tools/utils'
affected:
  - '@graphql-tools/utils <= 12.0.0'
patched:
  - '@graphql-tools/utils 12.0.1'
published: '2026-10-05'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T23:17:00.213'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104852'
references:
  - url: >-
      https://github.com/ardatan/graphql-tools/commit/0b9529f1988fd36186a7c106a6efe0356f1b7f2e
    label: security-advisories@github.com
  - url: 'https://github.com/ardatan/graphql-tools/pull/8423'
    label: security-advisories@github.com
  - url: >-
      https://github.com/ardatan/graphql-tools/releases/tag/@graphql-tools/utils@12.0.1
    label: security-advisories@github.com
  - url: >-
      https://github.com/ardatan/graphql-tools/security/advisories/GHSA-7mx3-vvmw-hjmv
    label: security-advisories@github.com
  - url: 'https://github.com/graphql-hive/gateway/pull/2600'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-7mx3-vvmw-hjmv'
tags:
  - nvd
  - ghsa
  - npm
  - cve.org
aliases:
  - GHSA-7mx3-vvmw-hjmv
ecosystem: npm
cvssSource: cna
ingestedAt: '2026-10-05T23:36:21.153Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-104852)

Affected packages:

- `@graphql-tools/utils <= 12.0.0`

Patched in:

- `@graphql-tools/utils 12.0.1`

Source: https://github.com/advisories/GHSA-7mx3-vvmw-hjmv