Impact

In affected releases of gRPC-Go, it is possible for an attacker to send HTTP/2 requests, cancel them, and send subsequent requests, which is valid by the HTTP/2 protocol, but would cause the gRPC-Go server to launch more concurrent method handlers than the configured maximum stream limit.

Patches

This vulnerability was addressed by #6703 and has been included in patch releases: 1.56.3, 1.57.1, 1.58.3. It is also included in the latest release, 1.59.0.

Along with applying the patch, users should also ensure they are using the grpc.MaxConcurrentStreams server option to apply a limit to the server's resources used for any single connection.

Workarounds

None.

References

6703