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OpenAdvisories
High · 7.5 CVE-2026-75508 EUVD-2026-108225GHSA-r77w-qph3-7vf8

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

Published Oct 22, 2026 · Updated Oct 29, 2026 · Assigned by GitHub_M

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 products

VendorProductAffectedFixed
graphql-python graphql-core >= 3.2.3, < 3.2.12, >= 3.3.0a3, < 3.3.0rc1 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 graphql-core 3.2.12-1 —
Debian 13 graphql-core No fix yet —
Debian 12 graphql-core No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 graphql-core No fix yet —
Ubuntu 26.04 LTS graphql-core No fix yet —
Ubuntu 24.04 LTS graphql-core No fix yet —
Ubuntu 22.04 LTS graphql-core No fix yet —
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed python-graphql-core 3.3.1-1.1 openSUSE-SU-2026:12474-1
openSUSE Leap 16.0 python-graphql-core 3.2.6-bp160.2.1 openSUSE-SU-2026:22258-1

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI graphql-core >= 3.2.3, < 3.2.12 3.2.12 GHSA-r77w-qph3-7vf8
PyPI graphql-core >= 3.3.0a3, < 3.3.0rc1 3.3.0rc1 GHSA-r77w-qph3-7vf8

Advisories 2

References