diff --git a/crypto/crypto.go b/crypto/crypto.go
index bd9b12756b..5cf5472fa6 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -203,6 +203,9 @@ func UnmarshalPubkey(pub []byte) (*ecdsa.PublicKey, error) {
 	if x == nil {
 		return nil, errInvalidPubkey
 	}
+	if !S256().IsOnCurve(x, y) {
+		return nil, errInvalidPubkey
+	}
 	return &ecdsa.PublicKey{Curve: S256(), X: x, Y: y}, nil
 }