# CVE-2026-75507: GraphQL-core: Denial of service via quadratic complexity in the OverlappingFieldsCanBeMerged validation rule


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 22 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-75507, GHSA-vj8h-fx38-h3vc, ROOT-APP-PYPI-CVE-2026-75507, UBUNTU-CVE-2026-75507

## What is CVE-2026-75507?

CVE-2026-75507 is a high-severity vulnerability in graphql-python graphql-core, published on 22 Oct 2026. 

### Official 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.

Weakness: CWE-407 (Inefficient Algorithmic Complexity), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-75507?

4 open source packages ship an affected version, including graphql-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `graphql-core` | PyPI | From 3.0.0 | 3.2.12 |
| `graphql-core` | PyPI | From 3.0.0 | 3.2.12 |
| `graphql-core` | PyPI | From 3.3.0a1 | 3.3.0rc1 |
| `graphql-core` | PyPI | From 3.3.0a1 | 3.3.0rc1 |

## How do I fix CVE-2026-75507?

Upgrade graphql-core to a fixed version for your release line: 3.2.12 or 3.3.0rc1.

## Is CVE-2026-75507 being exploited?

There is no known exploitation of CVE-2026-75507 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75507 and fix it if it is affected.

What it is: CVE-2026-75507 is a high-severity vulnerability in graphql-python graphql-core, published on 22 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-75507 in the wild and no public exploit code.

Affected packages and fixed versions:
- graphql-core (PyPI): affected from 3.0.0; fixed in 3.2.12
- graphql-core (PyPI): affected from 3.0.0; fixed in 3.2.12
- graphql-core (PyPI): affected from 3.3.0a1; fixed in 3.3.0rc1
- graphql-core (PyPI): affected from 3.3.0a1; fixed in 3.3.0rc1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-75507/ (Markdown: https://insights.sbomify.com/CVE-2026-75507/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75507
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75507
- OSV: https://osv.dev/vulnerability/CVE-2026-75507

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75507/
Summaries are generated and may contain mistakes; the official description above is the record.