# CVE-2026-75508: GraphQL-core: Denial of service via comment tokens bypassing the parser's max_tokens limit


- **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:** 29 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-75508, GHSA-r77w-qph3-7vf8, ROOT-APP-PYPI-CVE-2026-75508, UBUNTU-CVE-2026-75508

## What is CVE-2026-75508?

CVE-2026-75508 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 3.2.3 until 3.2.12 and 3.3.0rc1, the parser's max_tokens limit in Parser.advance_lexer counts only non-comment tokens returned after Lexer.lookahead skips comments. Each skipped comment is still allocated as a Token and retained through token.next and token.prev, allowing a highly compressible comment-padded GraphQL document to pass a low token limit while consuming memory. An unauthenticated remote attacker can exhaust worker memory before AST-based depth or complexity controls run. This issue is fixed in versions 3.2.12 and 3.3.0rc1.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-75508?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `graphql-core` | PyPI | From 3.2.3 | 3.2.12 |
| `graphql-core` | PyPI | From 3.2.3 | 3.2.12 |
| `graphql-core` | PyPI | From 3.3.0a3 | 3.3.0rc1 |
| `graphql-core` | PyPI | From 3.3.0a3 | 3.3.0rc1 |

## How do I fix CVE-2026-75508?

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

## Is CVE-2026-75508 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75508 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75508 and fix it if it is affected.

What it is: CVE-2026-75508 is a high-severity vulnerability in graphql-python graphql-core, published on 22 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75508 exists.

Affected packages and fixed versions:
- graphql-core (PyPI): affected from 3.2.3; fixed in 3.2.12
- graphql-core (PyPI): affected from 3.2.3; fixed in 3.2.12
- graphql-core (PyPI): affected from 3.3.0a3; fixed in 3.3.0rc1
- graphql-core (PyPI): affected from 3.3.0a3; 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-2026-75508/ (Markdown: https://insights.sbomify.com/CVE-2026-75508/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75508
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75508
- OSV: https://osv.dev/vulnerability/CVE-2026-75508

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75508/
Summaries are generated and may contain mistakes; the official description above is the record.