diff --git a/src/mesh/udp/UdpMulticastHandler.h b/src/mesh/udp/UdpMulticastHandler.h
index 0a27a316e..897c2eb47 100644
--- a/src/mesh/udp/UdpMulticastHandler.h
+++ b/src/mesh/udp/UdpMulticastHandler.h
@@ -78,6 +78,11 @@ class UdpMulticastHandler final
         if (!mp || !udp) {
             return false;
         }
+        // Validate channel index before accessing
+        if (chIndex < 0 || chIndex >= channels.size()) {
+            LOG_ERROR("Invalid channel index %d in UDP onSend", chIndex);
+            return false;
+        }
         // Check if uplink is enabled for this specific channel
         auto &ch = channels.getByIndex(chIndex);
         if (!ch.settings.uplink_enabled) {