From c1f3561a3e19defb022ca796aadeffe653a0f628 Mon Sep 17 00:00:00 2001
From: s-hadinger <49731213+s-hadinger@users.noreply.github.com>
Date: Fri, 12 Jan 2024 22:34:42 +0100
Subject: [PATCH] Fix random crash in Zigbee main page (#20481)

---
 CHANGELOG.md                                          | 1 +
 tasmota/tasmota_xdrv_driver/xdrv_23_zigbee_A_impl.ino | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1759ce230..d4a39d86f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ All notable changes to this project will be documented in this file.
 - Scripter memory leak in `>w x` (#20473)
 - ESP8266 GPIO Viewer exception 9 on reading Analog GPIO
 - GPIO Viewer single instance
+- Fix random crash in Zigbee main page
 
 ### Removed
 
diff --git a/tasmota/tasmota_xdrv_driver/xdrv_23_zigbee_A_impl.ino b/tasmota/tasmota_xdrv_driver/xdrv_23_zigbee_A_impl.ino
index 4870abd00..a27b25e2b 100644
--- a/tasmota/tasmota_xdrv_driver/xdrv_23_zigbee_A_impl.ino
+++ b/tasmota/tasmota_xdrv_driver/xdrv_23_zigbee_A_impl.ino
@@ -2335,8 +2335,11 @@ void ZigbeeShow(bool json)
               WSContentSend_P(PSTR(" &#128261; %d%%"), changeUIntScale(light.getDimmer(),0,254,0,100));
             }
             if (light.validCT() && ((channels == 2) || (channels == 5))) {
-              uint32_t ct_k = (((1000000 / light.getCT()) + 25) / 50) * 50;
-              WSContentSend_P(msg[ZB_WEB_LIGHT_CT], light.getCT(), ct_k);
+              uint16_t ct = light.getCT();
+              if (ct != 0) {        // ct == 0 means undefined value
+                uint32_t ct_k = (((1000000 / ct) + 25) / 50) * 50;
+                WSContentSend_P(msg[ZB_WEB_LIGHT_CT], light.getCT(), ct_k);
+              }
             }
             if (light.validHue() && light.validSat() && (channels >= 3)) {
               uint8_t r,g,b;