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GHSA-qr3m-xw4c-jqw3

CriticalCVSS 9.1 / 10
Published Apr 16, 2026·Last modified May 5, 2026
Affected Components(0)

No affected components available

Description

Impact

Hot Chocolate's Utf8GraphQLParser is a recursive descent parser with 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 runMaxExecutionDepth, complexity analyzers, persisted query allow-lists, and custom IDocumentValidatorRule implementations cannot intercept the crash because Utf8GraphQLParser.Parse is invoked before validation. The existing MaxAllowedFields=2048 limit does not help because the crashing payloads contain very few fields.

Severity: Critical (9.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Patches

  • v12 line: Fixed in 12.22.7
  • v13 line: Fixed in 13.9.16
  • v14 line: Fixed in 14.3.1
  • v15 line: Fixed in 15.1.14

The fix 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.

Workarounds

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).

References

  • Fix for v15: https://github.com/ChilliCream/graphql-platform/pull/9528
Risk Scores
Base Score
9.1

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
8.3

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.90%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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