CVE-2026-40324

Hot Chocolate is an open-source GraphQL server. Prior to versions 12.22.7, 13.9.16, 14.3.1, and 15.1.14, Hot Chocolate's recursive descent parser `Utf8GraphQLParser` has no recursion depth limit. A crafted GraphQL document with deeply nested selection sets, object values, list values, or list types can trigger a `StackOverflowException` on payloads as small as 40 KB. Because `StackOverflowException` is uncatchable in .NET (since .NET 2.0), the entire worker process is terminated immediately. All in-flight HTTP requests, background `IHostedService` tasks, and open WebSocket subscriptions on that worker are dropped. The orchestrator (Kubernetes, IIS, etc.) must restart the process. This occurs before any validation rules run — `MaxExecutionDepth`, complexity analyzers, persisted query allow-lists, and custom `IDocumentValidatorRule` implementations cannot intercept the crash because `Utf8GraphQLParser.Parse` is invoked before validation. The `MaxAllowedFields=2048` limit does not help because the crashing payloads contain very few fields. The fix in versions 12.22.7, 13.9.16, 14.3.1, and 15.1.14 adds a `MaxAllowedRecursionDepth` option to `ParserOptions` with a safe default, and enforces it across all recursive parser methods (`ParseSelectionSet`, `ParseValueLiteral`, `ParseObject`, `ParseList`, `ParseTypeReference`, etc.). When the limit is exceeded, a catchable `SyntaxException` is thrown instead of overflowing the stack. There is no application-level workaround. `StackOverflowException` cannot be caught in .NET. The only mitigation is to upgrade to a patched version. Operators can reduce (but not eliminate) risk by limiting HTTP request body size at the reverse proxy or load balancer layer, though the smallest crashing payload (40 KB) is well below most default body size limits and is highly compressible (~few hundred bytes via gzip).

• https://github.com/ChilliCream/graphql-platform/commit/08c0caa42ca33c121bbed49d2db892e5bf6fb541

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/commit/4cbaf67d366f800fc1e484bc5c06dfcf27b45023

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/commit/b185eb276c9ee227bd44616ff113be7f01a66c69

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/commit/b9271e6a500484c002fd528dcd34d1a9b445480f

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/pull/9528

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/pull/9530

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/pull/9531

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/releases/tag/12.22.7

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/releases/tag/13.9.16

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/releases/tag/14.3.1

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/releases/tag/15.1.14

  security-advisories@github.com
• https://github.com/ChilliCream/graphql-platform/security/advisories/GHSA-qr3m-xw4c-jqw3

  security-advisories@github.com