CVE-2026-75508 GraphQL-core: Denial of service via comment tokens bypassing the parser's max_tokens limit
- Exploited in the wild
- Not known
- Fix
- Available
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.
Which versions are affected by CVE-2026-75508?
4 open source packages ship an affected version, including graphql-core.
| Package | 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.
Sources
Also known as DEBIAN-CVE-2026-75508, GHSA-r77w-qph3-7vf8, ROOT-APP-PYPI-CVE-2026-75508, UBUNTU-CVE-2026-75508.