Vulnerability · Published Oct 22, 2026 · Assigned by GitHub_M
CVE-2026-75508GraphQL-core: Denial of service via comment tokens bypassing the parser's max_tokens limit
High 7.5
In plain English
A high-severity uncontrolled resource consumption in graphql-core from graphql-python. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | graphql-core | no fix listed | DEBIAN-CVE-2026-75508 |
| Debian:13 | graphql-core | no fix listed | DEBIAN-CVE-2026-75508 |
| Debian:14 | graphql-core | 3.2.12-1 | DEBIAN-CVE-2026-75508 |
| PyPI | graphql-core | 3.2.12 | GHSA-r77w-qph3-7vf8 |
| PyPI | graphql-core | 3.3.0rc1 | GHSA-r77w-qph3-7vf8 |
| Ubuntu:22.04:LTS | graphql-core | no fix listed | UBUNTU-CVE-2026-75508 |
| Ubuntu:24.04:LTS | graphql-core | no fix listed | UBUNTU-CVE-2026-75508 |
| Ubuntu:26.04:LTS | graphql-core | no fix listed | UBUNTU-CVE-2026-75508 |
| Ubuntu:26.10 | graphql-core | no fix listed | UBUNTU-CVE-2026-75508 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| graphql-python | graphql-core | >= 3.2.3, < 3.2.12>= 3.3.0a3, < 3.3.0rc1 |
Weakness: CWE-400, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/graphql-python/graphql-core/security/advisories/GHSA-r77w-qph3-7vf8 x_refsource_CONFIRM
- https://github.com/graphql-python/graphql-core/commit/437dea102e92fdf05a2971ca76787c5a5bad875a x_refsource_MISC
- https://github.com/graphql-python/graphql-core/commit/80ef435a1808fbbcc4aaac63ae76771a1c91002d x_refsource_MISC
- https://github.com/graphql-python/graphql-core/releases/tag/v3.2.12 x_refsource_MISC
- https://github.com/graphql-python/graphql-core/releases/tag/v3.3.0rc1 x_refsource_MISC