GraphQL-core is a Python port of the GraphQL.js reference implementation. From 3.0.0 until 3.2.12 and 3.3.0rc1, the OverlappingFieldsCanBeMerged rule in specified_rules repeatedly compares fields that share response names and recursively re-compares flattened inline fragments during the validation phase. The prior named-fragment memoization does not cover this path, so nested repeated inline fragments can drive quadratic and worst-case O(n²·m²) CPU work before any resolver or AST-based depth or complexity control runs. An unauthenticated remote attacker can submit a shallow, highly compressible GraphQL query that pins a worker process and can saturate a multi-worker service. This issue is fixed in versions 3.2.12 and 3.3.0rc1.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
graphql-python graphql-core affected
Version Status Constraints
>= 3.0.0, < 3.2.12 affected —
>= 3.3.0a1, < 3.3.0rc1 affected —

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-vj8h-fx38-h3vc GraphQL-core: Denial of service via quadratic complexity in the OverlappingFieldsCanBeMerged validation rule
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/graphql-python/graphql-core/commit/150e59814d97d12140be005a558c93188ef89198 cve-icon cve-icon
https://github.com/graphql-python/graphql-core/commit/29c2753a7ee30a96a4109e7c6add1a2dae0497d7 cve-icon cve-icon
https://github.com/graphql-python/graphql-core/releases/tag/v3.2.12 cve-icon cve-icon
https://github.com/graphql-python/graphql-core/releases/tag/v3.3.0rc1 cve-icon cve-icon
https://github.com/graphql-python/graphql-core/security/advisories/GHSA-vj8h-fx38-h3vc cve-icon cve-icon
History

Thu, 22 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Description GraphQL-core is a Python port of the GraphQL.js reference implementation. From 3.0.0 until 3.2.12 and 3.3.0rc1, the OverlappingFieldsCanBeMerged rule in specified_rules repeatedly compares fields that share response names and recursively re-compares flattened inline fragments during the validation phase. The prior named-fragment memoization does not cover this path, so nested repeated inline fragments can drive quadratic and worst-case O(n²·m²) CPU work before any resolver or AST-based depth or complexity control runs. An unauthenticated remote attacker can submit a shallow, highly compressible GraphQL query that pins a worker process and can saturate a multi-worker service. This issue is fixed in versions 3.2.12 and 3.3.0rc1.
Title GraphQL-core: Denial of service via quadratic complexity in the OverlappingFieldsCanBeMerged validation rule
Weaknesses CWE-400
CWE-407
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-22T16:12:38.424Z

Reserved: 2026-08-17T20:49:21.598Z

Link: CVE-2026-75507

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-22T17:16:59.757

Modified: 2026-10-22T17:40:46.877

Link: CVE-2026-75507

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-22T18:00:11Z

Weaknesses