Resource exhaustion in Graphql-Python Graphql-Core

CVE-2026-75507

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.

Vulnerability class: DoS (Denial of Service)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-75507?
CVE-2026-75507 is a high-severity vulnerability in Graphql-Python Graphql-Core, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-10-22.
How severe is CVE-2026-75507?
High severity. CVSS v3 base score is 7.5 out of 10.