What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-29
• Weakness: CWE-400

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

• graphql-python graphql-core: from 3.2.3, < 3.2.12; from 3.3.0a3, < 3.3.0rc1

References

• https://github.com/graphql-python/graphql-core/commit/437dea102e92fdf05a2971ca76787c5a5bad875a
• https://github.com/graphql-python/graphql-core/commit/80ef435a1808fbbcc4aaac63ae76771a1c91002d
• https://github.com/graphql-python/graphql-core/releases/tag/v3.2.12
• https://github.com/graphql-python/graphql-core/releases/tag/v3.3.0rc1
• https://github.com/graphql-python/graphql-core/security/advisories/GHSA-r77w-qph3-7vf8
• https://github.com/graphql-python/graphql-core/security/advisories/GHSA-r77w-qph3-7vf8

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