diff --git a/libevdev/libevdev.c b/libevdev/libevdev.c
index aefb387..c4729b5 100644
--- a/libevdev/libevdev.c
+++ b/libevdev/libevdev.c
@@ -1742,7 +1742,7 @@ libevdev_event_value_get_name(unsigned int type,
 	if (type != EV_ABS || code != ABS_MT_TOOL_TYPE)
 		return NULL;
 
-	if (value > MT_TOOL_MAX)
+	if (value < 0 || value > MT_TOOL_MAX)
 		return NULL;
 
 	return mt_tool_map[value];
diff --git a/test/test-event-names.c b/test/test-event-names.c
index c581b1d..480176c 100644
--- a/test/test-event-names.c
+++ b/test/test-event-names.c
@@ -227,6 +227,7 @@ START_TEST(test_value_name)
 	ck_assert_str_eq(libevdev_event_value_get_name(EV_ABS, ABS_MT_TOOL_TYPE, MT_TOOL_PALM), "MT_TOOL_PALM");
 	ck_assert_str_eq(libevdev_event_value_get_name(EV_ABS, ABS_MT_TOOL_TYPE, MT_TOOL_PEN), "MT_TOOL_PEN");
 	ck_assert_str_eq(libevdev_event_value_get_name(EV_ABS, ABS_MT_TOOL_TYPE, MT_TOOL_MAX), "MT_TOOL_MAX");
+	ck_assert(libevdev_event_value_get_name(EV_ABS, ABS_MT_TOOL_TYPE, -1) == NULL);
 }
 END_TEST