Disclosure 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 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.
Source-reported weakness categories
CWE-1321
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2026-104852
Open original source · Updated Oct 06, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
GitHub Reviewed Security Advisories · GHSA-7mx3-vvmw-hjmv
Open original source · Updated Oct 05, 2026
GraphQL Tools has prototype pollution in well-established utility function `mergeDeep`
Source severity: HIGH / 8.2
| Ecosystem | Package | Affected range | First patched |
|---|---|---|---|
| npm | @graphql-tools/utils | 12.0.1 |
Original records & references
PUBLISHED 2026-10-05T19:17:00-04:00
MODIFIED 2026-10-06T11:17:13-04:00
INGESTED 2026-10-06T11:45:40-04:00