diff --git a/src/cocoa_window.m b/src/cocoa_window.m
index 8fe992d5..5b8396b4 100644
--- a/src/cocoa_window.m
+++ b/src/cocoa_window.m
@@ -1536,7 +1536,7 @@ const char* _glfwPlatformGetScancodeName(int scancode)
     if (scancode < 0 || scancode > 0xff ||
         _glfw.ns.keycodes[scancode] == GLFW_KEY_UNKNOWN)
     {
-        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode");
+        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
diff --git a/src/null_window.c b/src/null_window.c
index 3e446641..b81ab601 100644
--- a/src/null_window.c
+++ b/src/null_window.c
@@ -524,6 +524,12 @@ const char* _glfwPlatformGetClipboardString(void)
 
 const char* _glfwPlatformGetScancodeName(int scancode)
 {
+    if (scancode < GLFW_KEY_SPACE || scancode > GLFW_KEY_LAST)
+    {
+        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
+        return NULL;
+    }
+
     switch (scancode)
     {
         case GLFW_KEY_APOSTROPHE:
diff --git a/src/win32_window.c b/src/win32_window.c
index 52a9c680..13126292 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -2108,7 +2108,7 @@ const char* _glfwPlatformGetScancodeName(int scancode)
     if (scancode < 0 || scancode > (KF_EXTENDED | 0xff) ||
         _glfw.win32.keycodes[scancode] == GLFW_KEY_UNKNOWN)
     {
-        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode");
+        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
diff --git a/src/x11_window.c b/src/x11_window.c
index 3f2277d6..d7b85994 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -2891,7 +2891,7 @@ const char* _glfwPlatformGetScancodeName(int scancode)
     if (scancode < 0 || scancode > 0xff ||
         _glfw.x11.keycodes[scancode] == GLFW_KEY_UNKNOWN)
     {
-        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode");
+        _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }