diff --git a/include/modules/custom.hpp b/include/modules/custom.hpp
index 6c17c6e4..a00faaa5 100644
--- a/include/modules/custom.hpp
+++ b/include/modules/custom.hpp
@@ -42,6 +42,7 @@ class Custom : public ALabel {
   int pid_;
   util::command::res output_;
   util::JsonParser parser_;
+  int signal_;  // Cached signal value to avoid JSON access in signal handler
 
   util::SleeperThread thread_;
 };
diff --git a/include/modules/image.hpp b/include/modules/image.hpp
index 510dad94..e31de0fc 100644
--- a/include/modules/image.hpp
+++ b/include/modules/image.hpp
@@ -33,6 +33,7 @@ class Image : public AModule {
   int size_;
   std::chrono::milliseconds interval_;
   util::command::res output_;
+  int signal_;  // Cached signal value to avoid JSON access in signal handler
 
   util::SleeperThread thread_;
 };
diff --git a/src/modules/custom.cpp b/src/modules/custom.cpp
index d75633e9..a3ea7b27 100644
--- a/src/modules/custom.cpp
+++ b/src/modules/custom.cpp
@@ -13,7 +13,8 @@ waybar::modules::Custom::Custom(const std::string& name, const std::string& id,
       tooltip_format_enabled_{config_["tooltip-format"].isString()},
       percentage_(0),
       fp_(nullptr),
-      pid_(-1) {
+      pid_(-1),
+      signal_(config_["signal"].isInt() ? config_["signal"].asInt() : -1) {
   if (config.isNull()) {
     spdlog::warn("There is no configuration for 'custom/{}', element will be hidden", name);
   }
@@ -136,7 +137,7 @@ void waybar::modules::Custom::waitingWorker() {
 }
 
 void waybar::modules::Custom::refresh(int sig) {
-  if (sig == SIGRTMIN + config_["signal"].asInt()) {
+  if (signal_ != -1 && sig == SIGRTMIN + signal_) {
     thread_.wake_up();
   }
 }
diff --git a/src/modules/image.cpp b/src/modules/image.cpp
index 173aabd3..4e830608 100644
--- a/src/modules/image.cpp
+++ b/src/modules/image.cpp
@@ -1,7 +1,9 @@
 #include "modules/image.hpp"
 
 waybar::modules::Image::Image(const std::string& id, const Json::Value& config)
-    : AModule(config, "image", id), box_(Gtk::ORIENTATION_HORIZONTAL, 0) {
+    : AModule(config, "image", id),
+      box_(Gtk::ORIENTATION_HORIZONTAL, 0),
+      signal_(config_["signal"].isInt() ? config_["signal"].asInt() : -1) {
   box_.pack_start(image_);
   box_.set_name("image");
   if (!id.empty()) {
@@ -41,7 +43,7 @@ void waybar::modules::Image::delayWorker() {
 }
 
 void waybar::modules::Image::refresh(int sig) {
-  if (sig == SIGRTMIN + config_["signal"].asInt()) {
+  if (signal_ != -1 && sig == SIGRTMIN + signal_) {
     thread_.wake_up();
   }
 }