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.
References6
- github.com/graphql-python/graphql-core/commit/437dea102e92fdf05…
- github.com/graphql-python/graphql-core/commit/80ef435a1808fbbcc…
- github.com/graphql-python/graphql-core/releases/tag/v3.2.12
- github.com/graphql-python/graphql-core/releases/tag/v3.3.0rc1
- github.com/graphql-python/graphql-core/security/advisories/GHSA…
- github.com/graphql-python/graphql-core/security/advisories/GHSA…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 48 · as of 8 November 2026
- CWE
- CWE-400CWE-770
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.