diff --git a/test-server/test-client.c b/test-server/test-client.c
index 086d52a3..47b6281f 100644
--- a/test-server/test-client.c
+++ b/test-server/test-client.c
@@ -383,13 +383,16 @@ int main(int argc, char **argv)
 			deny_mux = 1;
 			break;
 		case 'C':
-			strncpy(cert_path, optarg, sizeof cert_path);
+			strncpy(cert_path, optarg, sizeof(cert_path) - 1);
+			cert_path[sizeof(cert_path) - 1] = '\0';
 			break;
 		case 'K':
-			strncpy(key_path, optarg, sizeof key_path);
+			strncpy(key_path, optarg, sizeof(key_path) - 1);
+			key_path[sizeof(key_path) - 1] = '\0';
 			break;
 		case 'A':
-			strncpy(ca_path, optarg, sizeof ca_path);
+			strncpy(ca_path, optarg, sizeof(ca_path) - 1);
+			ca_path[sizeof(ca_path) - 1] = '\0';
 			break;
 #if defined(LWS_USE_POLARSSL)
 #else
@@ -397,7 +400,8 @@ int main(int argc, char **argv)
 #else
 #if defined(LWS_OPENSSL_SUPPORT) && defined(LWS_HAVE_SSL_CTX_set1_param)
 		case 'R':
-			strncpy(crl_path, optarg, sizeof crl_path);
+			strncpy(crl_path, optarg, sizeof(crl_path) - 1);
+			crl_path[sizeof(crl_path) - 1] = '\0';
 			break;
 #endif
 #endif
diff --git a/test-server/test-server.c b/test-server/test-server.c
index da618ce3..505df01a 100644
--- a/test-server/test-server.c
+++ b/test-server/test-server.c
@@ -265,13 +265,16 @@ int main(int argc, char **argv)
 			printf("Setting resource path to \"%s\"\n", resource_path);
 			break;
 		case 'C':
-			strncpy(cert_path, optarg, sizeof cert_path);
+			strncpy(cert_path, optarg, sizeof(cert_path) - 1);
+			cert_path[sizeof(cert_path) - 1] = '\0';
 			break;
 		case 'K':
-			strncpy(key_path, optarg, sizeof key_path);
+			strncpy(key_path, optarg, sizeof(key_path) - 1);
+			key_path[sizeof(key_path) - 1] = '\0';
 			break;
 		case 'A':
-			strncpy(ca_path, optarg, sizeof ca_path);
+			strncpy(ca_path, optarg, sizeof(ca_path) - 1);
+			ca_path[sizeof(ca_path) - 1] = '\0';
 			break;
 #if defined(LWS_OPENSSL_SUPPORT)
 		case 'v':
@@ -284,7 +287,8 @@ int main(int argc, char **argv)
 #else
 #if defined(LWS_HAVE_SSL_CTX_set1_param)
 		case 'R':
-			strncpy(crl_path, optarg, sizeof crl_path);
+			strncpy(crl_path, optarg, sizeof(crl_path) - 1);
+			crl_path[sizeof(crl_path) - 1] = '\0';
 			break;
 #endif
 #endif