diff --git a/docs/node-configuration.md b/docs/node-configuration.md
index d80ed5267..1c14bc76a 100644
--- a/docs/node-configuration.md
+++ b/docs/node-configuration.md
@@ -187,6 +187,8 @@ RPC:
   MaxFindResultItems: 100
   MaxFindStoragePageSize: 50
   MaxNEP11Tokens: 100
+  MaxRequestBodyBytes: 5242880
+  MaxRequestHeaderBytes: 1048576
   MaxWebSocketClients: 64
   SessionEnabled: false
   SessionExpirationTime: 15
@@ -225,6 +227,10 @@ where:
 - `MaxFindStoragePageSize` - the maximum number of elements for `findstorage` response per single page.
 - `MaxNEP11Tokens` - limit for the number of tokens returned from
   `getnep11balances` call.
+- `MaxRequestBodyBytes` - the maximum allowed HTTP request body size in bytes
+  (5MB by default).
+- `MaxRequestHeaderBytes` - the maximum allowed HTTP request header size in bytes
+  (1MB by default).
 - `MaxWebSocketClients` - the maximum simultaneous websocket client connection
   number (64 by default). Attempts to establish additional connections will
   lead to websocket handshake failures. Use "-1" to disable websocket
diff --git a/pkg/config/config.go b/pkg/config/config.go
index d30a30e61..cd2c157c3 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -3,6 +3,7 @@ package config
 import (
 	"bytes"
 	"fmt"
+	"net/http"
 	"os"
 	"time"
 
@@ -30,6 +31,12 @@ const (
 	// DefaultMaxNEP11Tokens is the default maximum number of resulting NEP11 tokens
 	// that can be traversed by `getnep11balances` JSON-RPC handler.
 	DefaultMaxNEP11Tokens = 100
+	// DefaultMaxRequestBodyBytes is the default maximum allowed size of HTTP
+	// request body in bytes.
+	DefaultMaxRequestBodyBytes = 5 * 1024 * 1024
+	// DefaultMaxRequestHeaderBytes is the maximum permitted size of the headers
+	// in an HTTP request.
+	DefaultMaxRequestHeaderBytes = http.DefaultMaxHeaderBytes
 )
 
 // Version is the version of the node, set at the build time.
diff --git a/pkg/config/rpc_config.go b/pkg/config/rpc_config.go
index bd9d0acdd..c9b0a1630 100644
--- a/pkg/config/rpc_config.go
+++ b/pkg/config/rpc_config.go
@@ -16,6 +16,8 @@ type (
 		MaxFindResultItems        int           `yaml:"MaxFindResultItems"`
 		MaxFindStorageResultItems int           `yaml:"MaxFindStoragePageSize"`
 		MaxNEP11Tokens            int           `yaml:"MaxNEP11Tokens"`
+		MaxRequestBodyBytes       int           `yaml:"MaxRequestBodyBytes"`
+		MaxRequestHeaderBytes     int           `yaml:"MaxRequestHeaderBytes"`
 		MaxWebSocketClients       int           `yaml:"MaxWebSocketClients"`
 		SessionEnabled            bool          `yaml:"SessionEnabled"`
 		SessionExpirationTime     int           `yaml:"SessionExpirationTime"`
diff --git a/pkg/neorpc/types.go b/pkg/neorpc/types.go
index 93e60e6a1..790d27341 100644
--- a/pkg/neorpc/types.go
+++ b/pkg/neorpc/types.go
@@ -115,6 +115,15 @@ func (s *SignerWithWitness) UnmarshalJSON(data []byte) error {
 	if err != nil {
 		return fmt.Errorf("not a signer: %w", err)
 	}
+	if len(aux.AllowedContracts) > transaction.MaxAttributes {
+		return fmt.Errorf("invalid number of AllowedContracts: got %d, allowed %d at max", len(aux.AllowedContracts), transaction.MaxAttributes)
+	}
+	if len(aux.AllowedGroups) > transaction.MaxAttributes {
+		return fmt.Errorf("invalid number of AllowedGroups: got %d, allowed %d at max", len(aux.AllowedGroups), transaction.MaxAttributes)
+	}
+	if len(aux.Rules) > transaction.MaxAttributes {
+		return fmt.Errorf("invalid number of Rules: got %d, allowed %d at max", len(aux.Rules), transaction.MaxAttributes)
+	}
 	acc, err := util.Uint160DecodeStringLE(strings.TrimPrefix(aux.Account, "0x"))
 	if err != nil {
 		acc, err = address.StringToUint160(aux.Account)
diff --git a/pkg/neorpc/types_test.go b/pkg/neorpc/types_test.go
index f0c99ea23..c817bc1e8 100644
--- a/pkg/neorpc/types_test.go
+++ b/pkg/neorpc/types_test.go
@@ -2,10 +2,12 @@ package neorpc
 
 import (
 	"encoding/json"
+	"fmt"
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/internal/testserdes"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/stretchr/testify/require"
 )
@@ -37,4 +39,54 @@ func TestSignerWithWitnessMarshalUnmarshalJSON(t *testing.T) {
 	actual, err := json.Marshal(s)
 	require.NoError(t, err)
 	require.Equal(t, expected, string(actual))
+
+	t.Run("subitems overflow", func(t *testing.T) {
+		checkSubitems := func(t *testing.T, bad any) {
+			data, err := json.Marshal(bad)
+			require.NoError(t, err)
+			err = json.Unmarshal(data, &SignerWithWitness{})
+
+			require.Error(t, err)
+			require.Contains(t, err.Error(), fmt.Sprintf("got %d, allowed %d at max", transaction.MaxAttributes+1, transaction.MaxAttributes))
+		}
+
+		t.Run("groups", func(t *testing.T) {
+			pk, err := keys.NewPrivateKey()
+			require.NoError(t, err)
+			bad := &SignerWithWitness{
+				Signer: transaction.Signer{
+					AllowedGroups: make([]*keys.PublicKey, transaction.MaxAttributes+1),
+				},
+			}
+			for i := range bad.AllowedGroups {
+				bad.AllowedGroups[i] = pk.PublicKey()
+			}
+
+			checkSubitems(t, bad)
+		})
+		t.Run("contracts", func(t *testing.T) {
+			bad := &SignerWithWitness{
+				Signer: transaction.Signer{
+					AllowedContracts: make([]util.Uint160, transaction.MaxAttributes+1),
+				},
+			}
+
+			checkSubitems(t, bad)
+		})
+		t.Run("rules", func(t *testing.T) {
+			bad := &SignerWithWitness{
+				Signer: transaction.Signer{
+					Rules: make([]transaction.WitnessRule, transaction.MaxAttributes+1),
+				},
+			}
+			for i := range bad.Rules {
+				bad.Rules[i] = transaction.WitnessRule{
+					Action:    transaction.WitnessAllow,
+					Condition: &transaction.ConditionScriptHash{},
+				}
+			}
+
+			checkSubitems(t, bad)
+		})
+	})
 }
diff --git a/pkg/services/rpcsrv/params/param.go b/pkg/services/rpcsrv/params/param.go
index 29d390648..3e07f22f4 100644
--- a/pkg/services/rpcsrv/params/param.go
+++ b/pkg/services/rpcsrv/params/param.go
@@ -394,7 +394,7 @@ func (p *Param) GetSignerWithWitness() (neorpc.SignerWithWitness, error) {
 // GetSignersWithWitnesses returns a slice of SignerWithWitness with CalledByEntry
 // scope from an array of Uint160 or an array of serialized transaction.Signer stored
 // in the parameter.
-func (p Param) GetSignersWithWitnesses() ([]transaction.Signer, []transaction.Witness, error) {
+func (p *Param) GetSignersWithWitnesses() ([]transaction.Signer, []transaction.Witness, error) {
 	hashes, err := p.GetArray()
 	if err != nil {
 		return nil, nil, err
diff --git a/pkg/services/rpcsrv/server.go b/pkg/services/rpcsrv/server.go
index bb54fc4a3..6e7a6ff55 100644
--- a/pkg/services/rpcsrv/server.go
+++ b/pkg/services/rpcsrv/server.go
@@ -267,25 +267,6 @@ var rpcWsHandlers = map[string]func(*Server, params.Params, *subscriber) (any, *
 // untyped nil or non-nil structure implementing OracleHandler interface.
 func New(chain Ledger, conf config.RPC, coreServer *network.Server,
 	orc OracleHandler, log *zap.Logger, errChan chan<- error) Server {
-	addrs := conf.Addresses
-	httpServers := make([]*http.Server, len(addrs))
-	for i, addr := range addrs {
-		httpServers[i] = &http.Server{
-			Addr: addr,
-		}
-	}
-
-	var tlsServers []*http.Server
-	if cfg := conf.TLSConfig; cfg.Enabled {
-		addrs := cfg.Addresses
-		tlsServers = make([]*http.Server, len(addrs))
-		for i, addr := range addrs {
-			tlsServers[i] = &http.Server{
-				Addr: addr,
-			}
-		}
-	}
-
 	protoCfg := chain.GetConfig().ProtocolConfiguration
 	if conf.SessionEnabled {
 		if conf.SessionExpirationTime <= 0 {
@@ -313,6 +294,14 @@ func New(chain Ledger, conf config.RPC, coreServer *network.Server,
 		conf.MaxNEP11Tokens = config.DefaultMaxNEP11Tokens
 		log.Info("MaxNEP11Tokens is not set or wrong, setting default value", zap.Int("MaxNEP11Tokens", config.DefaultMaxNEP11Tokens))
 	}
+	if conf.MaxRequestBodyBytes <= 0 {
+		conf.MaxRequestBodyBytes = config.DefaultMaxRequestBodyBytes
+		log.Info("MaxRequestBodyBytes is not set or wong, setting default value", zap.Int("MaxRequestBodyBytes", config.DefaultMaxRequestBodyBytes))
+	}
+	if conf.MaxRequestHeaderBytes <= 0 {
+		conf.MaxRequestHeaderBytes = config.DefaultMaxRequestHeaderBytes
+		log.Info("MaxRequestHeaderBytes is not set or wong, setting default value", zap.Int("MaxRequestHeaderBytes", config.DefaultMaxRequestHeaderBytes))
+	}
 	if conf.MaxWebSocketClients == 0 {
 		conf.MaxWebSocketClients = defaultMaxWebSocketClients
 		log.Info("MaxWebSocketClients is not set or wrong, setting default value", zap.Int("MaxWebSocketClients", defaultMaxWebSocketClients))
@@ -325,6 +314,28 @@ func New(chain Ledger, conf config.RPC, coreServer *network.Server,
 	if conf.EnableCORSWorkaround {
 		wsOriginChecker = func(_ *http.Request) bool { return true }
 	}
+
+	addrs := conf.Addresses
+	httpServers := make([]*http.Server, len(addrs))
+	for i, addr := range addrs {
+		httpServers[i] = &http.Server{
+			Addr:           addr,
+			MaxHeaderBytes: conf.MaxRequestHeaderBytes,
+		}
+	}
+
+	var tlsServers []*http.Server
+	if cfg := conf.TLSConfig; cfg.Enabled {
+		addrs := cfg.Addresses
+		tlsServers = make([]*http.Server, len(addrs))
+		for i, addr := range addrs {
+			tlsServers[i] = &http.Server{
+				Addr:           addr,
+				MaxHeaderBytes: conf.MaxRequestHeaderBytes,
+			}
+		}
+	}
+
 	return Server{
 		http:  httpServers,
 		https: tlsServers,
@@ -474,6 +485,8 @@ func (s *Server) SetOracleHandler(orc OracleHandler) {
 }
 
 func (s *Server) handleHTTPRequest(w http.ResponseWriter, httpRequest *http.Request) {
+	// Restrict request body before further processing.
+	httpRequest.Body = http.MaxBytesReader(w, httpRequest.Body, int64(s.config.MaxRequestBodyBytes))
 	req := params.NewRequest()
 
 	if httpRequest.URL.Path == "/ws" && httpRequest.Method == "GET" {