github.com/graphql-go/graphql (GraphQL for Go) through 0.8.1 does not validate that a scalar variable value matches its declared type. The built-in coerceString and coerceBool functions (scalars.go) accept input whose type does not match the declared String, ID, or Boolean scalar instead of raising the request error that the GraphQL specification mandates. In some cases (but not any typical case of JSON sent to a website), a deeply nested value leads to an unrecoverable "fatal error: stack overflow" condition.

graphql-go (aka GraphQL for Go) through 0.8.0 has infinite recursion in the type definition parser.

Denial of Service in graphql-go

graphql-go is a GraphQL server with a focus on ease of use. In versions prior to 1.3.0 there exists a DoS vulnerability that is possible due to a bug in the library that would allow an attacker with specifically designed queries to cause stack overflow panics. Any user with access to the GraphQL handler can send these queries and cause stack overflows. This in turn could potentially compromise the ability of the server to serve data to its users. The issue has been patched in version `v1.3.0`. The only known workaround for this issue is to disable the `graphql.MaxDepth` option from your schema which is not recommended.